/ Dictionary / Index M methoprene: Meaning and Definition of Find definitions for: meth•o•prene Pronunciation: (meth'u-prēn"), [key] — n. Chem. a synthetic insect juvenile hormone, CHO, used as a biological pesticide primarily on mosquito and fly larvae to prevent maturing to the adult state. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. methohexital methotrexate Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language