/ Dictionary / Index P prophylactic: Meaning and Definition of Find definitions for: pro•phy•lac•tic Pronunciation: (prō"fu-lak'tik, prof"u-), [key] — adj. defending or protecting from disease or infection, as a drug. preventive or protective. —n. a prophylactic medicine or measure. a preventive. a device, usually a rubber sheath, used to prevent conception or venereal infection; condom. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: prophylactic (Thesaurus) Prophets prophylaxis Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language