n. [ G. pyron, an abbr. of pyrokoman. ] (Org. Chem.) An unsaturated cyclic compound, C5H4O2, of which two varieties are known, α and γ. γ-pyrone is the parent substance of several natural yellow dyestuffs.

n. [ Pyro- + Gr. &unr_; law. ] The science of heat. [ 1913 Webster ]