pro·phy·lac·tic 
(prō′fə-lăktĭk, prŏf′ə-)
(prō′fə-lăktĭk, prŏf′ə-)adj.
Acting to defend against or prevent something, especially disease; protective.
n.
1. A prophylactic agent, device, or measure, such as a vaccine or drug.
2. A contraceptive device, especially a condom.
[French prophylactique, from Greek prophulaktikos, from prophulassein, to take precautions against : pro-, before; see PRO-2 + phulassein, to protect (from phulax, guard).]
pro′phy·lacti·cal·ly adv.
- secondary stress
- secondary structure
- secondary succession
- secondary syphilis
- secondary tissue
- second banana
- second base
- second baseman
- second best
- second-best
- second blessing
- second childhood
- second class
- second-class
- second class
- Second Coming
- second cousin
- second-degree burn
- Second Empire
- second fiddle
- second-generation
- second growth
- second-guess
- second-guesser
- second hand