/ Dictionary / Index B betamethyl acrolein: Meaning and Definition of Find definitions for: be'ta•meth'yl acro'lein Pronunciation: (bā'tu-meth'ul, bā"- or, esp. Brit., bē'tu-, bē"-), [key] crotonaldehyde. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. betamethasone beta-naphthol Related Content Daily Word Quiz: illegible Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language