/ Dictionary / Index A acyclovir: Meaning and Definition of Find definitions for: a•cy•clo•vir Pronunciation: (ā-sī'klō-vēr", -klu-), [key] — n. Pharm. a crystalline compound, CHNO, used as an antiviral drug in the treatment of herpes infections. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: acyclovir (Thesaurus) acyclic terpene acyl Related Content Daily Word Quiz: supine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language