/ Dictionary / Index M main-force: Meaning and Definition of Find definitions for: main-force Pronunciation: (mān'fôrs', -fōrs'), [key] — adj. pertaining to regular military units with standard uniforms and equipment. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Mainer mainframe Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language