The Collaborative International Dictionary of English v.0.48:

Pyrocitric \Pyr`o*cit"ric\, a. [Pyro- + citric: cf. F.
   pyrocitrique.] (Chem.)
   Pertaining to, or designating, any one of three acids
   obtained by the distillation of citric acid, and called
   respectively citraconic, itaconic, and mesaconic acid.
   [1913 Webster]

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]