/ Dictionary / Index M microinch: Meaning and Definition of Find definitions for: mi•cro•inch Pronunciation: (mī'krō-inch"), [key] — n. a unit of length equal to one millionth of an inch. Symbol: &mgr;in Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. micro-image microinject Related Content Daily Word Quiz: maritime Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language