What is the meaning of Penicillin?

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

A blue mold of the genus Penicillium that produces penicillin.

penicillin

penicillin

penicillin

Source: wiktionary.org