/ Dictionary / Index C cephalexin: Meaning and Definition of Find definitions for: ceph•a•lex•in Pronunciation: (sef"u-lek'sin), [key] — n. Pharm. an oral, antimicrobial drug, CHNOS, used in treating minor respiratory and urinary tract infections and as a backup or alternative to penicillin treatment. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: cephalexin (Thesaurus) cephalate cephalic Related Content Daily Word Quiz: lyre Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language