Wiktionary
glutaconic acid
n. (context organic compound English) the unsaturated aliphatic dicarboxylic acid ''pent-2-enedioic acid''
Wikipedia
Glutaconic acid
trans-Glutaconic acid is an organic compound with formula HOCCH=CHCHCOH. This dicarboxylic acid exists as a colorless solid and is related to the saturated chemical glutaric acid, HOCC(CH)COH. Esters and salts of glutaconic acid are called glutaconates.