maleic acid \maleic acid\ n. (Chem.)
   An unsaturated dicarboxylic acid (HO.CO.CH=CH.CO.OH) of cis
   conformation, having various uses in the manufacture of
   artificial resins, the dyeing and finishing of wool, silk,
   and cotton, and also combined with certain drugs to make
   salts more soluble than the basic forms. The corresponding
   isomer having trans conformation, is identical in chemical
   formula, is called fumaric acid. --MI11
   [PJC]