/ Dictionary / Index A acetyl group: Meaning and Definition of Find definitions for: ace'tyl group" Pronunciation: [key] — Chem. Chem. the univalent group, CHCO–, derived from acetic acid. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. acetylformic acid acetylic Related Content Daily Word Quiz: penurious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language