/ Dictionary / Index M megavitamin: Meaning and Definition of Find definitions for: meg•a•vi•ta•min Pronunciation: (meg'u-vī"tu-minBrit.also meg'u-vit"u-min), [key] — adj. of, pertaining to, or using very large amounts of vitamins:Cf. megavitamin therapy. —n. doses of vitamins much larger than the recommended dietary allowances. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. megatrend megavolt Related Content Daily Word Quiz: reticent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language