Definition of MI

  1. (noun)a former British unit of length equivalent to 6,080 feet (1,853.184 meters); 800 feet longer than a statute mile
  2. (noun)a unit of length used in navigation; exactly 1,852 meters; historically based on the distance spanned by one minute of arc in latitude
  3. (noun)a unit of length equal to 1,760 yards or 5,280 feet; exactly 1609.344 meters
  4. (noun)the syllable naming the third (mediant) note of any major scale in solmization