The Collaborative International Dictionary
pyroacetic spirit
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.
Wiktionary
pyroacetic spirit
n. (context obsolete chemistry English) acetone.