Nouns Starting With O
Here's the list of all the 4522 Nouns Starting With O in the English Language.
The list is arranged by the word lengths. Click on the length below to jump to the relevant section of the page.
| Common Nouns (with Definitions and Examples) | |
|---|---|
| on | More Definitions → |
| one | 1. the smallest whole number or a numeral representing this number 2. a single person or thing More Definitions → |
| other | More Definitions → |
| out | 1. (baseball) a failure by a batter or runner to reach a base safely in baseball More Definitions → |
| over | 1. (cricket) the division of play during which six balls are bowled at the batsman by one player from the other team from the same end of the pitch More Definitions → |
| order | 1. (often plural) a command given by a superior (e.g., a military or law enforcement officer) that must be obeyed 2. a degree in a continuum of size or quantity More Definitions → |
| off | More Definitions → |
| office | 1. place of business where professional or clerical duties are performed 2. an administrative unit of government More Definitions → |
| open | 1. a clear or unobstructed space or expanse of land or water 2. where the air is unconfined More Definitions → |
| old | 1. past times More Definitions → |
| offer | 1. the verbal act of offering 2. something offered (as a proposal or bid) More Definitions → |
| original | 1. an original creation (i.e., an audio recording) from which copies can be made 2. something that serves as a model or a basis for making copies More Definitions → |
| once | More Definitions → |
| official | 1. a worker who holds or is invested with an office 2. someone who administers the rules of a game or sport More Definitions → |
| oil | 1. a slippery or viscous liquid or liquefiable substance not miscible with water 2. oil paint containing pigment that is used by an artist More Definitions → |
| overall | 1. (usually plural) work clothing consisting of denim trousers (usually with a bib and shoulder straps) 2. a loose protective coverall or smock worn over ordinary clothing for dirty work More Definitions → |
| organization | 1. a group of people who work together 2. an organized structure for arranging or classifying More Definitions → |
| object | 1. a tangible and visible entity; an entity that can cast a shadow 2. the goal intended to be attained (and which is believed to be attainable) More Definitions → |
| outside | 1. the region that is outside of something 2. the outer side or surface of something More Definitions → |
| operations | 1. financial transactions at a brokerage; having to do with the execution of trades and keeping customer records More Definitions → |
| option | 1. the right to buy or sell property at an agreed price; the right is purchased and if it is not exercised by a stated date the money is forfeited 2. one of a number of things from which only one can be chosen More Definitions → |
| overview | 1. a general summary of a subject More Definitions → |
| opportunity | 1. a possibility due to a favorable combination of circumstances More Definitions → |
| operation | 1. the state of being in effect or being operative 2. a business especially one run on a large scale More Definitions → |
| owner | 1. (law) someone who owns (is legal possessor of) a business 2. a person who owns something More Definitions → |
| opinion | 1. a personal belief or judgment that is not founded on proof or certainty 2. a message expressing a belief about something; the expression of a belief that is held with confidence but not substantiated by positive knowledge or proof More Definitions → |
| output | 1. final product; the things produced 2. production of a certain amount More Definitions → |
| officer | 1. any person in the armed services who holds a position of authority or command 2. someone who is appointed or elected to an office and who holds a position of trust More Definitions → |
| os | 1. a mouth or mouthlike opening 2. rigid connective tissue that makes up the skeleton of vertebrates More Definitions → |
| oral | 1. an examination conducted by spoken communication More Definitions → |
| optional | More Definitions → |
| orange | 1. round yellow to orange fruit of any of several citrus trees 2. orange color or pigment; any of a range of colors between red and yellow More Definitions → |
| opening | 1. an open or empty space in or between things 2. a ceremony accompanying the start of some enterprise More Definitions → |
| offering | 1. something offered (as a proposal or bid) 2. money contributed to a religious organization; item or items contributed to a religious organization for religious purposes More Definitions → |
| ocean | 1. a large body of water constituting a principal part of the hydrosphere 2. anything apparently limitless in quantity or volume More Definitions → |
| origin | 1. the place where something begins, where it springs into being 2. properties attributable to your ancestry More Definitions → |
| ordering | 1. logical or comprehensible arrangement of separate elements 2. the act of putting things in a sequential arrangement More Definitions → |
| outdoors | 1. where the air is unconfined More Definitions → |
| operator | 1. (mathematics) a symbol or function representing a mathematical operation 2. an agent that operates some apparatus or machine More Definitions → |
| organic | 1. a fertilizer that is derived from animal or vegetable matter More Definitions → |
| organisation | 1. the persons (or committees or departments etc.) who make up a body for the purpose of administering something 2. a group of people who work together More Definitions → |
| objective | 1. the goal intended to be attained (and which is believed to be attainable) 2. the lens or system of lenses in a telescope or microscope that is nearest the object being viewed More Definitions → |
| outlet | 1. a place of business for retailing goods 2. receptacle providing a place in a wiring system where current can be taken to run electrical devices More Definitions → |
| oxford | 1. a low shoe laced over the instep More Definitions → |
| oak | 1. the hard durable wood of any oak; used especially for furniture and flooring 2. a deciduous tree of the genus Quercus; has acorns and lobed leaves More Definitions → |
| outlook | 1. a habitual or characteristic mental attitude that determines how you will interpret and respond to situations 2. belief about (or mental picture of) the future More Definitions → |
| ownership | 1. the relation of an owner to the thing possessed; possession with the right to transfer possession to others 2. the act of having and controlling property More Definitions → |
| opera | 1. a drama set to music; consists of singing with orchestral accompaniment and an orchestral overture and interludes 2. a building where musical dramas are performed More Definitions → |
| oracle | 1. an authoritative person who divines the future 2. a prophecy (usually obscure or allegorical) revealed by a priest or priestess; believed to be infallible More Definitions → |
| ongoing | More Definitions → |
| optimization | 1. the act of rendering optimal More Definitions → |
| okay | 1. an endorsement More Definitions → |
| occupation | 1. the principal activity in your life that you do to earn money 2. the control of a country by military forces of a foreign power More Definitions → |
| overseas | More Definitions → |
| ordinary | 1. a judge of a probate court 2. the expected or commonplace condition or situation More Definitions → |
| obligation | 1. the social force that binds you to the courses of action demanded by that force 2. the state of being obligated to do or pay something More Definitions → |
| outcome | 1. something that results 2. a phenomenon that follows and is caused by some previous phenomenon More Definitions → |
| odds | 1. the likelihood of a thing occurring rather than not occurring 2. the ratio by which one better's wager is greater than that of another More Definitions → |
| overnight | More Definitions → |
| orientation | 1. the act of orienting 2. an integrated set of attitudes and beliefs More Definitions → |
| offset | 1. the time at which something is supposed to begin 2. a compensating equivalent More Definitions → |
| observation | 1. the act of making and recording a measurement 2. the act of observing; taking a patient look More Definitions → |
| opposition | 1. the action of opposing something that you disapprove or disagree with 2. the relation between opposed entities More Definitions → |
| opposite | 1. a word that expresses a meaning opposed to the meaning of another word, in which case the two words are antonyms of each other 2. a relation of direct opposition More Definitions → |
| outline | 1. the line that appears to bound an object 2. a sketchy summary of the main points of an argument or theory More Definitions → |
| odd | More Definitions → |
| occasion | 1. an event that occurs at a critical time 2. a formal or official social gathering or ceremony of people More Definitions → |
| orchestra | 1. a musical organization consisting of a group of instrumentalists including string players 2. seating on the main floor in a theater More Definitions → |
| oxygen | 1. a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust More Definitions → |
| outer | More Definitions → |
| omega | 1. the ending of a series or sequence 2. the last (24th) letter of the Greek alphabet More Definitions → |
| oven | 1. kitchen appliance used for baking or roasting More Definitions → |
| offensive | 1. the action of attacking an enemy More Definitions → |
| offshore | More Definitions → |
| outreach | 1. the act of reaching out More Definitions → |
| occasions | 1. something you have to do More Definitions → |
| olive | 1. small ovoid fruit of the European olive tree; important food and source of oil 2. evergreen tree cultivated in the Mediterranean region since antiquity and now elsewhere; has edible shiny black fruits More Definitions → |
| oasis | 1. a fertile tract in a desert (where the water table approaches the surface) 2. a shelter serving as a place of safety or sanctuary More Definitions → |
| observer | 1. a person who becomes aware (of things or events) through the senses 2. an expert who observes and comments on something More Definitions → |
| organ | 1. a fully differentiated structural and functional unit in an animal that is specialized for some particular function 2. a government agency or instrument devoted to the performance of some specific function More Definitions → |
| ordinance | 1. an authoritative command 2. a statute enacted by a city government More Definitions → |
| offense | 1. a lack of politeness; a failure to show regard for others; wounding the feelings of others 2. a feeling of anger caused by being offended More Definitions → |
| oriental | More Definitions → |
| optics | 1. the branch of physics that studies the physical properties of light 2. optical properties More Definitions → |
| oval | 1. a closed plane curve resulting from the intersection of a circular cone and a plane cutting completely through it More Definitions → |
| overhead | 1. the expense of maintaining property (e.g., paying property taxes and utilities and insurance); it does not include depreciation or the cost of financing or income taxes 2. (computer science) the processing time required by a device prior to the execution of a command More Definitions → |
| organizer | 1. a person who brings order and organization to an enterprise 2. someone who enlists workers to join a union More Definitions → |
| onion | 1. the bulb of an onion plant 2. bulbous plant having hollow leaves cultivated worldwide for its rounded edible bulb More Definitions → |
| ozone | 1. a colorless gas (O3) soluble in alkalis and cold water; a strong oxidizing agent; can be produced by electric discharge in oxygen or by the action of ultraviolet radiation on oxygen in the stratosphere (where it acts as a screen for ultraviolet radiation) More Definitions → |
| opponent | 1. a contestant that you are matched against 2. someone who offers opposition More Definitions → |
| obesity | 1. more than average fatness More Definitions → |
| occurrence | 1. an event that happens 2. an instance of something occurring More Definitions → |
| orbit | 1. the (usually elliptical) path described by one celestial body in its revolution about another 2. a particular environment or walk of life More Definitions → |
| oxide | 1. any compound of oxygen with another element or a radical More Definitions → |
| optimum | 1. most favorable conditions or greatest degree or amount possible under given circumstances More Definitions → |
| owl | 1. nocturnal bird of prey with hawk-like beak and claws and large head with front-facing eyes More Definitions → |
| oversight | 1. an unintentional omission resulting from failure to notice something 2. management by overseeing the performance or operation of a person or group More Definitions → |
| operative | 1. a person secretly employed in espionage for a government 2. someone who can be employed as a detective to collect information and assist in criminal investigations More Definitions → |
| organs | 1. edible viscera of a butchered animal More Definitions → |
| offence | 1. the action of attacking an enemy 2. the team that has the ball (or puck) and is trying to score More Definitions → |
| occupancy | 1. an act of being a tenant or occupant 2. the act of occupying or taking possession of a building More Definitions → |
| optic | 1. the organ of sight More Definitions → |
| outgoing | More Definitions → |
| odyssey | 1. a long wandering and eventful journey More Definitions → |
| offender | 1. a person who transgresses moral or civil law More Definitions → |
| overstock | More Definitions → |
| oncology | 1. the branch of medicine concerned with the study and treatment of tumors More Definitions → |
| orthodox | More Definitions → |
| overtime | 1. work done in addition to regular working hours 2. playing time beyond regulation, to break a tie More Definitions → |
| outfit | 1. any cohesive unit such as a military company 2. a set of clothing (with accessories) More Definitions → |
| oblique | 1. any grammatical case other than the nominative 2. a diagonally arranged abdominal muscle on either side of the torso More Definitions → |
| orchid | 1. any of numerous plants of the orchid family usually having flowers of unusual shapes and beautiful colors More Definitions → |
| observatory | 1. a building designed and equipped to observe astronomical phenomena 2. a structure commanding a wide view of its surroundings More Definitions → |
| orchard | 1. garden consisting of a small cultivated wood without undergrowth More Definitions → |
| onset | 1. the beginning or early stages 2. (military) an offensive against an enemy (using weapons) More Definitions → |
| organism | 1. a living thing that has (or can develop) the ability to act or function independently 2. a system considered analogous in structure or function to a living body More Definitions → |
| overlap | 1. a representation of common ground between theories or phenomena 2. the property of partial coincidence in time More Definitions → |
| objection | 1. the act of expressing earnest opposition or protest 2. the speech act of objecting More Definitions → |
| outerwear | 1. clothing for use outdoors More Definitions → |
| overflow | 1. a large flow 2. the occurrence of surplus liquid (as water) exceeding the limit or capacity More Definitions → |
| outpatient | 1. a patient who does not reside in the hospital where he is being treated More Definitions → |
| offspring | 1. the immediate descendants of a person 2. something that comes into existence as a result More Definitions → |
| odor | 1. any property detected by the olfactory system 2. the sensation that results when olfactory receptors in the nose are stimulated by particular chemicals in gaseous form More Definitions → |
| ounce | 1. a unit of apothecary weight equal to 480 grains or one twelfth of a troy pound 2. a unit of weight equal to one sixteenth of a pound or 16 drams or 28.349 grams More Definitions → |
| opener | 1. the first event in a series 2. a person who unfastens or unwraps or opens More Definitions → |
| obscure | More Definitions → |
| ore | 1. a mineral that contains metal that is valuable enough to be mined 2. a monetary subunit in Denmark and Norway and Sweden; 100 ore equal 1 krona More Definitions → |
| outbreak | 1. a sudden violent spontaneous occurrence (usually of some undesirable condition) More Definitions → |
| ornament | 1. something used to beautify More Definitions → |
| override | 1. a manually operated device to correct the operation of an automatic device 2. the act of nullifying; making null and void; counteracting or overriding the effect or force of something More Definitions → |
| overland | More Definitions → |
| overlay | 1. protective covering consisting, for example, of a layer of boards applied to the studs and joists of a building to strengthen it and serve as a foundation for a weatherproof exterior 2. a layer of decorative material (such as gold leaf or wood veneer) applied over a surface More Definitions → |
| orient | 1. the hemisphere that includes Eurasia and Africa and Australia More Definitions → |
| osteoporosis | 1. abnormal loss of bony tissue resulting in fragile porous bones attributable to a lack of calcium; most common in postmenopausal women More Definitions → |
| oath | 1. profane or obscene expression usually of surprise or anger 2. a commitment to tell the truth (especially in a court of law); to lie under oath is to become subject to prosecution for perjury More Definitions → |
| orbital | More Definitions → |
| oyster | 1. marine mollusks having a rough irregular shell; found on the sea bed mostly in coastal waters 2. edible body of any of numerous oysters More Definitions → |
| oxidation | 1. the process of oxidizing; the addition of oxygen to a compound with a loss of electrons; always occurs accompanied by reduction More Definitions → |
| opal | 1. a translucent mineral consisting of hydrated silica of variable color; some varieties are used as gemstones More Definitions → |
| obsession | 1. an irrational motive for performing trivial or repetitive actions, even against your will 2. an unhealthy and compulsive preoccupation with something or someone More Definitions → |
| overweight | 1. the property of excessive fatness More Definitions → |
| ordination | 1. the status of being ordained to a sacred office 2. logical or comprehensible arrangement of separate elements More Definitions → |
| obedience | 1. the act of obeying; dutiful or submissive behavior with respect to another person 2. the trait of being willing to obey More Definitions → |
| overload | 1. an electrical load that exceeds the available electrical power 2. an excessive burden More Definitions → |
| onyx | 1. a chalcedony with alternating black and white bands; used in making cameos More Definitions → |
| obituary | 1. a notice of someone's death; usually includes a short biography More Definitions → |
| octet | 1. the cardinal number that is the sum of seven and one 2. eight performers or singers who perform together More Definitions → |
| ox | 1. an adult castrated bull of the genus Bos; especially Bos taurus 2. any of various wild bovines especially of the genera Bos or closely related Bibos More Definitions → |
| overdose | More Definitions → |
| orb | 1. the ball-shaped capsule containing the vertebrate eye 2. an object with a spherical shape More Definitions → |
| obstacle | 1. something immaterial that stands in the way and must be circumvented or surmounted 2. an obstruction that stands in the way (and must be removed or surmounted or circumvented) More Definitions → |
| ombudsman | 1. a government appointee who investigates complaints by private persons against the government More Definitions → |
| optimisation | 1. the act of rendering optimal More Definitions → |
| octave | 1. a feast day and the seven days following it 2. a musical interval of eight tones More Definitions → |
| outward | More Definitions → |
| ohm | 1. a unit of electrical resistance equal to the resistance between two points on a conductor when a potential difference of one volt between them produces a current of one ampere More Definitions → |
| ora | 1. a mouth or mouthlike opening 2. rigid connective tissue that makes up the skeleton of vertebrates More Definitions → |
| overlapping | 1. covering with a design in which one element covers a part of another (as with tiles or shingles) More Definitions → |
| ontology | 1. (computer science) a rigorous and exhaustive organization of some knowledge domain that is usually hierarchical and contains all the relevant entities and their relations 2. the metaphysical study of the nature of being and existence More Definitions → |
| outlaw | 1. someone who has committed a crime or has been legally convicted of a crime More Definitions → |
| outback | 1. the bush country of the interior of Australia More Definitions → |
| opaque | More Definitions → |
| omission | 1. a mistake resulting from neglect 2. something that has been omitted More Definitions → |
| opus | 1. a musical work that has been created More Definitions → |
| obstruction | 1. any structure that makes progress difficult 2. the physical condition of blocking or filling a passage with an obstruction More Definitions → |
| overture | 1. orchestral music played at the beginning of an opera or oratorio 2. something that serves as a preceding event or introduces what follows More Definitions → |
| openness | 1. without obstructions to passage or view 2. characterized by an attitude of ready accessibility (especially about one's actions or purposes); without concealment; not secretive More Definitions → |
| outpost | 1. a station in a remote or sparsely populated location 2. a settlement on the frontier of civilization More Definitions → |
| oppression | 1. the act of subjugating by cruelty 2. the state of being kept down by unjust use of force or authority: More Definitions → |
| occult | 1. supernatural forces and events and beings collectively 2. supernatural practices and techniques More Definitions → |
| orthopedic | More Definitions → |
| ophthalmology | 1. the branch of medicine concerned with the eye and its diseases More Definitions → |
| obstetrics | 1. the branch of medicine dealing with childbirth and care of the mother More Definitions → |
| overcast | 1. the state of the sky when it is covered by clouds 2. gloomy semidarkness caused by cloud cover More Definitions → |
| optimism | 1. the optimistic feeling that all is going to turn out well 2. a general disposition to expect the best in all things More Definitions → |
| ottoman | 1. thick cushion used as a seat 2. a low seat or a stool to rest the feet of a seated person More Definitions → |
| outing | 1. a journey taken for pleasure 2. a day devoted to an outdoor social gathering More Definitions → |
| overhaul | 1. periodic maintenance on a car or machine 2. the act of improving by renewing and restoring More Definitions → |
| overdrive | 1. the state of high or excessive activity or productivity or concentration 2. a high gear used at high speeds to maintain the driving speed with less output power More Definitions → |
| otter | 1. the fur of an otter 2. freshwater carnivorous mammal having webbed and clawed feet and dark brown fur More Definitions → |
| ornamental | 1. any plant grown for its beauty or ornamental value More Definitions → |
| ode | 1. a lyric poem with complex stanza forms More Definitions → |
| orphan | 1. a child who has lost both parents 2. someone or something who lacks support or care or supervision More Definitions → |
| originator | 1. someone who creates new things More Definitions → |
| overlook | 1. a high place affording a good view More Definitions → |
| outset | 1. the time at which something is supposed to begin More Definitions → |
| outrage | 1. a feeling of righteous anger 2. a wantonly cruel act More Definitions → |
| orderly | 1. a soldier who serves as an attendant to a superior officer 2. a male hospital attendant who has general duties that do not involve the medical treatment of patients More Definitions → |
| oceanfront | 1. land bordering an ocean More Definitions → |
| organiser | 1. someone who enlists workers to join a union 2. a person who brings order and organization to an enterprise More Definitions → |
| outage | 1. the amount of something (as whiskey or oil) lost in storage or transportation 2. a temporary suspension of operation (as of computers) More Definitions → |
| orthopaedic | More Definitions → |
| outsource | More Definitions → |
| oblivion | 1. the state of being disregarded or forgotten 2. total forgetfulness More Definitions → |
| oscillator | 1. generator that produces sonic oscillations or alternating current More Definitions → |
| ordnance | 1. military supplies 2. large but transportable armament More Definitions → |
| outboard | 1. a motorboat with an outboard motor 2. internal-combustion engine that mounts at stern of small boat More Definitions → |
| originate | More Definitions → |
| oceanography | 1. the branch of science dealing with physical and biological aspects of the oceans More Definitions → |
| octopus | 1. tentacles of octopus prepared as food 2. bottom-living cephalopod having a soft oval body with eight long tentacles More Definitions → |
| opium | 1. an addictive narcotic extracted from seed capsules of the opium poppy More Definitions → |
| orthogonal | More Definitions → |
| obsessive | 1. a person who has obsessions More Definitions → |
| originality | 1. the ability to think and act independently 2. the quality of being new and original (not derived from something else) More Definitions → |
| osprey | 1. large harmless hawk found worldwide that feeds on fish and builds a bulky nest often occupied for years More Definitions → |
| offeror | 1. someone who presents something to another for acceptance or rejection More Definitions → |
| outsole | 1. the outer sole of a shoe or boot that is the bottom of the shoe and makes contact with the ground More Definitions → |
| oatmeal | 1. porridge made of rolled oats 2. meal made from rolled or ground oats More Definitions → |
| outsider | 1. someone who is excluded from or is not a member of a group 2. a contestant (human or animal) not considered to have a good chance to win More Definitions → |
| obi | 1. (West Indies) followers of a religious system involving witchcraft and sorcery 2. a religious belief of African origin involving witchcraft and sorcery; practiced in parts of the West Indies and tropical Americas More Definitions → |
| omnibus | 1. an anthology of articles on a related subject or an anthology of the works of a single author 2. a vehicle carrying many passengers; used for public transport More Definitions → |
| observable | More Definitions → |
| osteoarthritis | 1. chronic breakdown of cartilage in the joints; the most common form of arthritis occurring usually after middle age More Definitions → |
| oversize | More Definitions → |
| oboe | 1. a slender double-reed instrument; a woodwind with a conical bore and a double-reed mouthpiece More Definitions → |
| occupant | 1. someone who lives at a particular place for a prolonged period or who was born there More Definitions → |
| observance | 1. the act of observing; taking a patient look 2. a formal event performed on a special occasion More Definitions → |
| overwrite | More Definitions → |
| outskirts | 1. outlying areas (as of a city or town) More Definitions → |
| optima | 1. most favorable conditions or greatest degree or amount possible under given circumstances More Definitions → |
| opacity | 1. the phenomenon of not permitting the passage of electromagnetic radiation 2. incomprehensibility resulting from obscurity of meaning More Definitions → |
| oxidase | 1. any of the enzymes that catalyze biological oxidation More Definitions → |
| orthopedics | 1. the branch of medical science concerned with disorders or deformities of the spine and joints More Definitions → |
| ovary | 1. the organ that bears the ovules of a flower 2. (vertebrates) one of usually two organs that produce ova and secrete estrogen and progesterone More Definitions → |
| oscillation | 1. the process of oscillating between states 2. (physics) a regular periodic variation in value about a mean More Definitions → |
| ointment | 1. semisolid preparation (usually containing a medicine) applied externally as a remedy or for soothing an irritation 2. toiletry consisting of any of various substances in the form of a thick liquid that have a soothing and moisturizing effect when applied to the skin More Definitions → |
| occidental | More Definitions → |
| ocular | 1. combination of lenses at the viewing end of optical instruments More Definitions → |
| objectivity | 1. judgment based on observable phenomena and uninfluenced by emotions or personal prejudices More Definitions → |
| ovulation | 1. the expulsion of an ovum from the ovary (usually midway in the menstrual cycle) More Definitions → |
| origination | 1. an event that is a beginning; a first part or stage of subsequent events 2. the act of starting something for the first time; introducing something new More Definitions → |
| outlay | 1. the act of spending or disbursing money 2. money paid out; an amount spent More Definitions → |
| overthrow | 1. the termination of a ruler or institution (especially by force) 2. the act of disturbing the mind or body More Definitions → |
| ordinate | 1. the value of a coordinate on the vertical axis More Definitions → |
| oar | 1. an implement used to propel or steer a boat More Definitions → |
| offbeat | 1. an unaccented beat (especially the last beat of a measure) More Definitions → |
| oneness | 1. the quality of being united into one More Definitions → |
| outflow | 1. the discharge of a fluid from some container 2. the process of flowing out More Definitions → |
| octane | 1. any isomeric saturated hydrocarbon found in petroleum and used as a fuel and solvent More Definitions → |
| optometry | 1. the practice of an optometrist More Definitions → |
| oncogene | 1. a gene that disposes normal cells to change into cancerous tumor cells More Definitions → |
| orca | 1. predatory black-and-white toothed whale with large dorsal fin; common in cold seas More Definitions → |
| ostrich | 1. a person who refuses to face reality or recognize the truth (a reference to the popular notion that the ostrich hides from danger by burying its head in the sand) 2. fast-running African flightless bird with two-toed feet; largest living bird More Definitions → |
| ogre | 1. a cruel wicked and inhuman person 2. (folklore) a giant who likes to eat human beings More Definitions → |
| officiating | 1. the act of umpiring More Definitions → |
| ordeal | 1. a severe or trying experience 2. a primitive method of determining a person's guilt or innocence by subjecting the accused person to dangerous or painful tests believed to be under divine control; escape was usually taken as a sign of innocence More Definitions → |
| obstructive | More Definitions → |
| omen | 1. a sign of something about to happen More Definitions → |
| operand | 1. a quantity upon which a mathematical operation is performed More Definitions → |
| orthodoxy | 1. the quality of being orthodox (especially in religion) 2. a belief or orientation agreeing with conventional standards More Definitions → |
| ovation | 1. enthusiastic recognition (especially one accompanied by loud applause) More Definitions → |
| origami | 1. the Japanese art of folding paper into shapes representing objects (e.g., flowers or birds) More Definitions → |
| orbiter | 1. man-made equipment that orbits around the earth or the moon More Definitions → |
| onslaught | 1. a sudden and severe onset of trouble 2. (military) an offensive against an enemy (using weapons) More Definitions → |
| oat | 1. annual grass of Europe and North Africa; grains used as food and fodder (referred to primarily in the plural: `oats') 2. seed of the annual grass Avena sativa (spoken of primarily in the plural as `oats') More Definitions → |
| overrun | 1. too much production or more than expected More Definitions → |
| overkill | 1. the capability to obliterate a target with more weapons (especially nuclear weapons) than are required 2. any effort that seems to go farther than would be necessary to achieve its goal More Definitions → |
| orthopaedics | 1. the branch of medical science concerned with disorders or deformities of the spine and joints More Definitions → |
| olfactory | More Definitions → |
| occlusion | 1. closure or blockage (as of a blood vessel) 2. (meteorology) a composite front when colder air surrounds a mass of warm air and forces it aloft More Definitions → |
| osmosis | 1. (biology, chemistry) diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal More Definitions → |
| obsidian | 1. acid or granitic glass formed by the rapid cooling of lava without crystallization; usually dark, but transparent in thin pieces More Definitions → |
| optimise | More Definitions → |
| orphanage | 1. the condition of being a child without living parents 2. a public institution for the care of orphans More Definitions → |
| ooze | 1. any thick, viscous matter 2. the process of seeping More Definitions → |
| odour | 1. the sensation that results when olfactory receptors in the nose are stimulated by particular chemicals in gaseous form 2. any property detected by the olfactory system More Definitions → |
| outperform | More Definitions → |
| oregano | 1. aromatic Eurasian perennial 2. pungent leaves used as seasoning with meats and fowl and in stews and soups and omelets More Definitions → |
| obit | 1. a notice of someone's death; usually includes a short biography More Definitions → |
| otolaryngology | 1. the medical specialty that deals with diseases of the ear, nose and throat More Definitions → |
| oca | 1. South American wood sorrel cultivated for its edible tubers More Definitions → |
| overturn | 1. the act of upsetting something 2. an improbable and unexpected victory More Definitions → |
| organza | 1. a fabric made of silk or a silklike fabric that resembles organdy More Definitions → |
| outrigger | 1. a stabilizer for a canoe; spars attach to a shaped log or float parallel to the hull More Definitions → |
| optimist | 1. a person disposed to take a favorable view of things More Definitions → |
| ordinal | 1. the number designating place in an ordered sequence More Definitions → |
| outcast | 1. a person who is rejected (from society or home) More Definitions → |
| oblong | 1. a plane figure that deviates from a square or circle due to elongation More Definitions → |
| obscurity | 1. the quality of being unclear or abstruse and hard to understand 2. an obscure and unimportant standing; not well known More Definitions → |
| overflowing | More Definitions → |
| ova | 1. the female reproductive cell; the female gamete More Definitions → |
| outfitter | 1. someone who sells men's clothes 2. a shop that provides equipment for some specific purpose More Definitions → |
| orthodontic | More Definitions → |
| octal | More Definitions → |
| orifice | 1. an aperture or hole that opens into a bodily cavity More Definitions → |
| outburst | 1. an unrestrained expression of emotion 2. a sudden intense happening More Definitions → |
| oscilloscope | 1. electronic equipment that provides visual images of varying electrical quantities More Definitions → |
| oligonucleotide | 1. (biochemistry) a polynucleotide whose molecules contain relatively few nucleotides More Definitions → |
| overheating | 1. excessive heating More Definitions → |
| outcry | 1. a loud utterance; often in protest or opposition More Definitions → |
| octagon | 1. an eight-sided polygon More Definitions → |
| overwhelm | More Definitions → |
| obscenity | 1. the trait of behaving in an obscene manner 2. an offensive or indecent word or phrase More Definitions → |
| orthodontics | 1. the branch of dentistry dealing with the prevention or correction of irregularities of the teeth More Definitions → |
| overpayment | 1. a payment larger than needed or expected 2. the act of paying too much More Definitions → |
| opiate | 1. a narcotic drug that contains opium or an opium derivative More Definitions → |
| obstruct | More Definitions → |
| ogle | More Definitions → |
| odometer | 1. a meter that shows mileage traversed More Definitions → |
| oxen | 1. domesticated bovine animals as a group regardless of sex or age 2. an adult castrated bull of the genus Bos; especially Bos taurus More Definitions → |
| overdraft | 1. a draft in excess of the credit balance More Definitions → |
| oilfield | 1. a region rich in petroleum deposits (especially one with producing oil wells) More Definitions → |
| overuse | 1. exploitation to the point of diminishing returns More Definitions → |
| outfield | 1. the area of a baseball playing field beyond the lines connecting the bases More Definitions → |
| orchestration | 1. an arrangement of a piece of music for performance by an orchestra or band 2. the act of arranging a piece of music for an orchestra and assigning parts to the different musical instruments More Definitions → |
| organist | 1. a person who plays an organ More Definitions → |
| otitis | 1. inflammation of the ear More Definitions → |
| ocarina | 1. egg-shaped terracotta wind instrument with a mouthpiece and finger holes More Definitions → |
| obsolescence | 1. the process of becoming obsolete; falling into disuse or becoming out of date More Definitions → |
| onus | 1. an onerous or difficult concern More Definitions → |
| overlord | 1. a person who has general authority over others More Definitions → |
| oxidoreductase | 1. an enzyme that catalyzes oxidation-reduction More Definitions → |
| occupier | 1. someone who lives at a particular place for a prolonged period or who was born there 2. a member of a military force who is residing in a conquered foreign country More Definitions → |
| ottomans | 1. thick cushion used as a seat 2. a low seat or a stool to rest the feet of a seated person More Definitions → |
| operon | 1. a segment of DNA containing adjacent genes including structural genes and an operator gene and a regulatory gene More Definitions → |
| overseer | 1. a person who directs and manages an organization More Definitions → |
| oddity | 1. eccentricity that is not easily explained 2. a strange attitude or habit More Definitions → |
| oxymoron | 1. conjoining contradictory terms (as in `deafening silence') More Definitions → |
| observant | More Definitions → |
| operatic | More Definitions → |
| oeuvre | 1. the total output of a writer or artist (or a substantial part of it) More Definitions → |
| optometrist | 1. a person skilled in testing for defects of vision in order to prescribe corrective glasses More Definitions → |
| overpass | 1. bridge formed by the upper level of a crossing of two highways at different levels More Definitions → |
| overhang | 1. projection that extends beyond or hangs over something else More Definitions → |
| oriole | 1. mostly tropical songbird; the male is usually bright orange and black 2. American songbird; male is black and orange or yellow More Definitions → |
| ostomy | 1. surgical procedure that creates an artificial opening for the elimination of bodily wastes More Definitions → |
| outfielder | 1. (baseball) a person who plays in the outfield 2. a fielder in cricket who is stationed in the outfield More Definitions → |
| opulent | More Definitions → |
| outlier | 1. a person who lives away from his place of work 2. an extreme deviation from the mean More Definitions → |
| omnipotent | More Definitions → |
| outfall | 1. the outlet of a river or drain or other source of water More Definitions → |
| obelisk | 1. a stone pillar having a rectangular cross section tapering towards a pyramidal top 2. a character used in printing to indicate a second cross reference or footnote when the asterisk has already been used More Definitions → |
| outgrowth | 1. a natural consequence of development 2. the gradual beginning or coming forth More Definitions → |
| osteopathy | 1. therapy based on the assumption that restoring health is best accomplished by manipulating the skeleton and muscles More Definitions → |
| oncoming | 1. the beginning or early stages More Definitions → |
| oxidant | 1. a substance that oxidizes another substance More Definitions → |
| oncologist | 1. a specialist in oncology More Definitions → |
| ornithology | 1. the branch of zoology that studies birds More Definitions → |
| ovum | 1. the female reproductive cell; the female gamete More Definitions → |
| oddball | 1. a person with an unusual or odd personality More Definitions → |
| optician | 1. a worker who makes glasses for remedying defects of vision More Definitions → |
| omicron | 1. the 15th letter of the Greek alphabet More Definitions → |
| outpouring | 1. a natural flow of ground water 2. a sudden rapid flow (as of water) More Definitions → |
| ochre | 1. any of various earths containing silica and alumina and ferric oxide; used as a pigment 2. a moderate yellow-orange to orange color More Definitions → |
| orang | 1. large long-armed ape of Borneo and Sumatra having arboreal habits More Definitions → |
| oratory | 1. addressing an audience formally (usually a long and rhetorical address and often pompous) More Definitions → |
| orator | 1. a person who delivers a speech or oration More Definitions → |
| oozing | 1. the process of seeping More Definitions → |
| oilseed | 1. any of several seeds that yield oil More Definitions → |
| oryx | 1. large African antelope with long straight nearly upright horns More Definitions → |
| offside | 1. (sport) the mistake of occupying an illegal position on the playing field (in football, soccer, ice hockey, field hockey, etc.) More Definitions → |
| outstation | 1. a station in a remote or sparsely populated location More Definitions → |
| oka | 1. a Turkish unit of weight equal to about 2.75 pounds 2. a Turkish liquid unit equal to 1.3 pints More Definitions → |
| objector | 1. a person who dissents from some established policy More Definitions → |
| outnumber | More Definitions → |
| outlander | 1. a person who comes from a foreign country; someone who does not owe allegiance to your country More Definitions → |
| obverse | 1. the more conspicuous of two alternatives or cases or sides 2. the side of a coin or medal bearing the principal stamp or design More Definitions → |
| outhouse | 1. a small outbuilding with a bench having holes through which a user can defecate More Definitions → |
| overtaking | 1. going by something that is moving in order to get in front of it More Definitions → |
| olivine | 1. a mineral consisting of magnesium iron silicate; a source of magnesium More Definitions → |
| ornithine | 1. an amino acid that does not occur in proteins but is important in the formation of urea More Definitions → |
| omelet | 1. beaten eggs or an egg mixture cooked until just set; may be folded around e.g. ham or cheese or jelly More Definitions → |
| overestimate | 1. an appraisal that is too high 2. a calculation that results in an estimate that is too high More Definitions → |
| overcoat | 1. a heavy coat worn over clothes in winter 2. an additional protective coating (as of paint or varnish) More Definitions → |
| oocyte | 1. a female gametocyte that develops into an ovum after two meiotic divisions More Definitions → |
| okra | 1. long green edible beaked pods of the okra plant 2. tall coarse annual of Old World tropics widely cultivated in southern United States and West Indies for its long mucilaginous green pods used as basis for soups and stews; sometimes placed in genus Hibiscus More Definitions → |
| oxytocin | 1. hormone secreted by the posterior pituitary gland (trade name Pitocin); stimulates contractions of the uterus and ejection of milk More Definitions → |
| oxbow | 1. the land inside an oxbow bend in a river 2. a U-shaped curve in a stream More Definitions → |
| outcrop | 1. the part of a rock formation that appears above the surface of the surrounding land More Definitions → |
| oxygenation | 1. the process of providing or combining or treating with oxygen More Definitions → |
| occipital | More Definitions → |
| outfitting | 1. the act of renovating and fitting out a ship More Definitions → |
| orthodontist | 1. a dentist specializing in the prevention or correction of irregularities of the teeth More Definitions → |
| ouguiya | 1. the basic unit of money in Mauritania More Definitions → |
| overburden | 1. the surface soil that must be moved away to get at coal seams and mineral deposits 2. an excessive burden More Definitions → |
| ornamentation | 1. the state of being ornamented 2. something used to beautify More Definitions → |
| offshoot | 1. a natural consequence of development More Definitions → |
| ophthalmologist | 1. a medical doctor specializing in the diagnosis and treatment of diseases of the eye More Definitions → |
| outturn | 1. what is produced in a given time period More Definitions → |
| oleander | 1. an ornamental but poisonous flowering shrub having narrow evergreen leaves and clusters of fragrant white to pink or red flowers: native to East Indies but widely cultivated in warm regions More Definitions → |
| omelette | 1. beaten eggs or an egg mixture cooked until just set; may be folded around e.g. ham or cheese or jelly More Definitions → |
| operetta | 1. a short amusing opera More Definitions → |
| overpopulation | 1. too much population More Definitions → |
| obfuscation | 1. confusion resulting from failure to understand 2. the activity of obscuring people's understanding, leaving them baffled or bewildered More Definitions → |
| opulence | 1. wealth as evidenced by sumptuous living More Definitions → |
| overeating | 1. eating to excess (personified as one of the deadly sins) More Definitions → |
| oestrogen | 1. a general term for female steroid sex hormones that are secreted by the ovary and responsible for typical female sexual characteristics More Definitions → |
| oxalate | 1. a salt or ester of oxalic acid More Definitions → |
| oink | 1. the short low gruff noise of the kind made by hogs More Definitions → |
| overheat | More Definitions → |
| oriel | 1. a projecting bay window corbeled or cantilevered out from a wall More Definitions → |
| olefin | 1. any unsaturated aliphatic hydrocarbon More Definitions → |
| overexposure | 1. the act of exposing film to too much light or for too long a time 2. the act of exposing someone excessively to an influencing experience More Definitions → |
| octavo | 1. the size of a book whose pages are made by folding a sheet of paper three times to form eight leaves More Definitions → |
| orangutan | 1. large long-armed ape of Borneo and Sumatra having arboreal habits More Definitions → |
| oodles | 1. a large number or amount More Definitions → |
| officiate | More Definitions → |
| oldie | 1. a song that was formerly popular More Definitions → |
| obstetrician | 1. a physician specializing in obstetrics More Definitions → |
| oligarchy | 1. a political system governed by a few people More Definitions → |
| oaf | 1. an awkward stupid person More Definitions → |
| oratorio | 1. a musical composition for voices and orchestra based on a religious text More Definitions → |
| offal | 1. viscera and trimmings of a butchered animal often considered inedible by humans More Definitions → |
| opossum | 1. small furry Australian arboreal marsupials having long usually prehensile tails 2. nocturnal arboreal marsupial having a naked prehensile tail found from southern North America to northern South America More Definitions → |
| overshadow | More Definitions → |
| ouster | 1. a person who ousts or supplants someone else 2. a wrongful dispossession More Definitions → |
| orthography | 1. a method of representing the sounds of a language by written or printed symbols More Definitions → |
| oration | 1. an instance of oratory More Definitions → |
| otherworld | 1. an abstract spiritual world beyond earthly reality More Definitions → |
| outcall | More Definitions → |
| overshoot | 1. an approach that fails and gives way to another attempt More Definitions → |
| oolong | 1. Chinese tea leaves that have been partially fermented before being dried More Definitions → |
| overpower | More Definitions → |
| osteosarcoma | 1. malignant bone tumor; most common in children and young adults where it tends to affect the femur More Definitions → |
| oedema | 1. swelling from excessive accumulation of watery fluid in cells, tissues, or serous cavities More Definitions → |
| organelle | 1. a specialized part of a cell; analogous to an organ More Definitions → |
| oomph | 1. attractiveness to the opposite sex 2. the activeness of an energetic personality More Definitions → |
| occultation | 1. one celestial body obscures another More Definitions → |
| obliterate | More Definitions → |
| overstate | More Definitions → |
| occlusive | 1. a consonant produced by stopping the flow of air at some point and suddenly releasing it More Definitions → |
| orchestrate | More Definitions → |
| osteomyelitis | 1. an inflammation of bone and bone marrow (usually caused by bacterial infection) More Definitions → |
| overgrowth | 1. excessive size; usually caused by excessive secretion of growth hormone from the pituitary gland 2. a profusion of growth on or over something else More Definitions → |
| opportunism | 1. taking advantage of opportunities without regard for the consequences for others More Definitions → |
| omnipotence | 1. the state of being omnipotent; having unlimited power More Definitions → |
| ology | 1. an informal word (abstracted from words with this ending) for some unidentified branch of knowledge More Definitions → |
| oscillate | More Definitions → |
| opportunist | 1. a person who places expediency above principle More Definitions → |
| oppressor | 1. a person of authority who subjects others to undue pressures More Definitions → |
| overproduction | 1. too much production or more than expected More Definitions → |
| offing | 1. the near or foreseeable future 2. the part of the sea that can be seen from the shore and is beyond the anchoring area More Definitions → |
| oiler | 1. a worker who oils engines or machinery 2. a well that yields or has yielded oil More Definitions → |
| occultism | 1. the study of the supernatural 2. a belief in supernatural powers and the possibility of bringing them under human control More Definitions → |
| oxidizer | 1. a substance that oxidizes another substance More Definitions → |
| oligopoly | 1. (economics) a market in which control over the supply of a commodity is in the hands of a small number of producers and each one can influence prices and affect competitors More Definitions → |
| outdoorsman | 1. a person who spends time outdoors (e.g., hunting or fishing) More Definitions → |
| ovine | More Definitions → |
| officiant | 1. a clergyman who officiates at a religious ceremony or service More Definitions → |
| organon | 1. a system of principles for philosophic or scientific investigations; an instrument for acquiring knowledge More Definitions → |
| obliteration | 1. destruction by annihilating something 2. the complete destruction of every trace of something More Definitions → |
| orthogonality | 1. the relation of opposition between things at right angles 2. the quality of lying or intersecting at right angles More Definitions → |
| orientalism | 1. the quality or customs or mannerisms characteristic of Asian civilizations More Definitions → |
| octroi | 1. a tax on various goods brought into a town More Definitions → |
| ocelot | 1. nocturnal wildcat of Central America and South America having a dark-spotted buff-brown coat More Definitions → |
| ontogeny | 1. (biology) the process of an individual organism growing organically; a purely biological unfolding of events involved in an organism changing gradually from a simple to a more complex level More Definitions → |
| otherness | 1. the quality of being not alike; being distinct or different from that otherwise experienced or known More Definitions → |
| overage | 1. a surplus or excess of money or merchandise that is actually on hand and that exceeds expectations More Definitions → |
| overcharge | 1. a price that is too high More Definitions → |
| overprint | 1. something added by overprinting More Definitions → |
| operant | More Definitions → |
| ousting | 1. the act of ejecting someone or forcing them out More Definitions → |
| oxygenase | 1. an oxidoreductase that catalyzes the incorporation of molecular oxygen More Definitions → |
| oesophagus | 1. the passage between the pharynx and the stomach More Definitions → |
| osteotomy | 1. surgical sectioning of bone More Definitions → |
| obfuscate | More Definitions → |
| offsides | More Definitions → |
| overtone | 1. (usually plural) an ulterior implicit meaning or quality 2. a harmonic with a frequency that is a multiple of the fundamental frequency More Definitions → |
| omniscience | 1. the state of being omniscient; having infinite knowledge More Definitions → |
| oleo | 1. a spread made chiefly from vegetable oils and used as a substitute for butter More Definitions → |
| osmium | 1. a hard brittle blue-grey or blue-black metallic element that is one of the platinum metals; the heaviest metal known More Definitions → |
| organophosphate | 1. an insecticide that interferes with an insect's nervous system More Definitions → |
| oversupply | 1. the quality of being so overabundant that prices fall More Definitions → |
| outbuilding | 1. a building that is subordinate to and separate from a main building More Definitions → |
| overwork | 1. the act of working too much or too long More Definitions → |
| ovoid | 1. an egg-shaped object More Definitions → |
| otorhinolaryngology | 1. the medical specialty that deals with diseases of the ear, nose and throat More Definitions → |
| olla | 1. leaf or strip from a leaf of the talipot palm used in India for writing paper More Definitions → |
| ossification | 1. the developmental process of bone formation 2. the calcification of soft tissue into a bonelike material More Definitions → |
| overstatement | 1. making to seem more important than it really is More Definitions → |
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