Citraconic acid

from The Collaborative International Dictionary of English v.0.48

Citraconic \Cit`ra*con"ic\, a. [Citric + aconitic.]
   Pertaining to, derived from, or having certain
   characteristics of, citric and aconitic acids.
   [1913 Webster]

   {Citraconic acid} (Chem.), a white, crystalline, deliquescent
      substance, {C3H4(CO2H)2}, obtained by distillation of
      citric acid. It is a compound of the ethylene series.
      [1913 Webster]