prophylactic

Etymology

From Latin, from Ancient Greek πρό (pró, “before”) + φύλαξις (phúlaxis, “a watching, guarding”).

noun

1. A medicine which preserves or defends against disease; a preventive.
   1. (US, specifically) A prophylactic condom.
      It is not clear whether such education is to be directed to homosexuals (for whom prophylactics are not a contraceptive) or to heterosexuals as well (for whom prophylactics are a contraceptive). 1977, Human Life Center, International Review of Natural Family Planning, Human Life Center, St. John's University, page 2
      Given the widespread use of coitus interruptus and male prophylactics as contraceptive practices in France […] 1994, Mary Louise Roberts, Civilization Without Sexes: Reconstructing Gender in Postwar France, 1917–1927, University of Chicago Press, page 96
      Some men put the prophylactic on just the tip of the penis: this is a mistake, because the prophylactic will come off. 2000, Peter Parnell, John Irving, The Cider House Rules: Here in St. Cloud's, Dramatists Play Service, Inc., page 46
2. (figurative) Any device or mechanism intended to prevent harmful consequences.
   The securities laws are a prophylactic against stock fraud.

adj

1. Serving to prevent or protect against an undesired effect, especially disease or pregnancy