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]