maleic acid

from WordNet (r) 3.0 (2006)

maleic acid
    n 1: a colorless crystalline compound found in unripe fruit
         (such as apples or tomatoes or cherries) and used mainly to
         make polyester resins

from The Collaborative International Dictionary of English v.0.48

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]