noun Pharmacology.
- a semisynthetic penicillin, C18H19N3O5S, taken orally as a broad-spectrum antibiotic.
n.
- A semisynthetic penicillin having an antibacterial spectrum of action similar to that of ampicillin.
- An antibiotic derived from penicillin, having an antibacterial spectrum of action similar to that of ampicillin. Chemical formula: C16H19N3O5.