/ Dictionary / Index M micron: Meaning and Definition of Find definitions for: mi•cron Pronunciation: (mī'kron), [key] — pl. -crons, -cra Also calledthe millionth part of a meter. Symbol: &mgr;, mu a colloidal particle whose diameter is between 0.2 and 10 microns. a very small unit of pressure, equal to that exerted by a column of mercury 1&mgr; high. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: micron (Thesaurus) micromount Micronesia Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language