/ Dictionary / Index D doxycycline: Meaning and Definition of Find definitions for: dox•y•cy•cline Pronunciation: (dok"sē-sī'klēn, -klin), [key] — n. Pharm. a synthetic analog of a broad-spectrum antibiotic tetracycline drug, CHNO, used against a wide range of susceptible Gram-positive and Gram-negative organisms. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: doxycycline (Thesaurus) doxy doyen Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language