/ Dictionary / Index A acetylcysteine: Meaning and Definition of Find definitions for: a•ce•tyl•cys•te•ine Pronunciation: (u-sēt"l-sis'tē-ēn", -in, u-set"-, as"i-tl-), [key] — n. Pharm. a substance, CHNOS, used in solution as an inhalant to dissolve mucus in the treatment of chronic bronchitis, asthma, and emphysema and also used as an antidote in acetaminophen poisoning. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. acetyl-coenzyme A acetylene Related Content Daily Word Quiz: abstain Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language