What is "penam"

n. (context organic chemistry English) A beta-lactam.

Penams are a subclass of the broader β-lactam family of antibiotics and related compounds. Penams contain a β-lactam ring fused to a 5-membered ring, where one of the atoms in the ring is a sulfur and the ring is fully saturated. Penicillin is a member of this family of compounds (hence the name of the family).