ENVELOPE

Definition of ENVELOPE

  1. (noun)a flat (usually rectangular) container for a letter, thin package, etc.
  2. (noun)any wrapper or covering
  3. (noun)a curve that is tangent to each of a family of curves
  4. (noun)a natural covering (as by a fluid)
  5. (noun)the maximum operating capability of a system (especially an aircraft)
  6. (noun)the bag containing the gas in a balloon