penicillin

/ˌpɛnɪˈsɪlɪn/

IPA: /P EH0 N AH0 S IH1 L AH0 N/

noun
  1. 1

    Any of a group of narrow-spectrum antibiotics obtained from Penicillium molds or synthesized; they have a beta-lactam structure; most are active against gram-positive bacteria and used in the treatment of various infections and diseases.

Source: https://en.wiktionary.org/wiki/penicillin