Meaning of penicillin

pen•i•cil•lin

Pronunciation: (pen"u-sil'in), [key]
— n. Pharm.
  1. any of several antibiotics of low toxicity, produced naturally by molds of the genus Penicillium and also semisynthetically, having a bactericidal action on many susceptible Gram-positive or Gram-negative cocci and bacilli, some also being effective against certain spirochetes.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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