WordReference Random House Unabridged Dictionary of American English © 2025
pi•per•a•cil•lin
(pī per′ə sil′in),USA pronunciation n. [Pharm.]
- Drugsa broad-spectrum semisynthetic penicillin, C23H26N5NaO7, used against certain susceptible Gram-positive and Gram-negative bacteria and certain anaerobes, esp. P. aeruginosa.
- pipera(zinyl), a component of its chemical name (see piperazine, -yl) + -cillin, as in penicillin