What is "mesaconic acid"

n. (context chemistry English) one of the isomeric dicarboxylic acids produced by the distillation of citric acid, or as metabolites by microorganisms, trans-CH₃-C(CO₂H)=CHCO₂H; the cis-isomer is citraconic acid

Mesaconic acid is one of several isomeric carboxylic acids obtained from citric acid. It is the trans-isomer of citraconic acid. It is used as a fire retardant.