Definition of penicilloic acid in US English:

penicilloic acid

noun

Biochemistry
  • Any of a group of acids which are dicarboxylic acid derivatives of thiazolidine and are produced when penicillins are hydrolysed (as by a penicillinase) and the carbon–nitrogen bond of the lactam ring is broken.

Origin

1940s; earliest use found in Science.