The Collaborative International Dictionary of English v.0.48:

Pyroacetic \Pyr`o*a*ce"tic\, a. [Pyro- + acetic: cf. F.
   pyroac['e]tique.] (Chem.)
   Pertaining to, and designating, a substance (acetone)
   obtained by the distillation of the acetates. It is now
   called also pyroacetic ether, and formerly was called
   pyroacetic spirit.
   [1913 Webster]