/ Dictionary / Index M megatherm: Meaning and Definition of Find definitions for: meg•a•therm Pronunciation: (meg'u-thûrm"), [key] — n. a plant requiring a constant high temperature and abundant moisture for growth. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. megathere megaton Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language