/ Dictionary / Index M millionth: Meaning and Definition of Find definitions for: mil•lionth Pronunciation: (mil'yunth), [key] — adj. coming last in a series of a million. being one of a million equal parts. —n. the millionth member of a series. a millionth part, esp. of one (). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: millionth (Thesaurus) millionfold millipede 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