/ Dictionary / Index M man-day: Meaning and Definition of Find definitions for: man-day Pronunciation: (man'dā"), [key] — pl. man-days. a unit of measurement, esp. in accountancy; based on a standard number of man-hours in a day of work. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mandatory Mande Related Content Daily Word Quiz: prevalent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language