noun Pharmacology.
  1. a broad-spectrum semisynthetic penicillin, C23H26N5NaO7, used against certain susceptible Gram-positive and Gram-negative bacteria and certain anaerobes, especially P. aeruginosa.

Origin of piperacillin

pipera(zinyl), a component of its chemical name (see piperazine, -yl) + -cillin, as in penicillin
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018