Pronunciation: (pī'rō),[key] —n., —pl.-ros.Informal. a pyromaniac.
1. a combining form meaning “fire,” “heat,” “high temperature,” used in the formation of compound words: pyrogen; pyrolusite; pyromancy. 2. Chem.a combining form used in the names of inorganic acids, indicating that the acid's water content is intermediate between that of the corresponding ortho- (more water) and meta- (least water) acids (pyroantimonic, H4Sb2O7, pyroarsenic, H4As2O7, and pyrosulfuric, H2S2O7, acids). The combining form is also used in the names of the salts of these acids. If the acid ends in -ic, the corresponding salt ends in -ate (pyroboric acid, H2B4O7, and potassium pyrobate, K2B4O7, or pyrosulfuric, H2S2O7, and pyrosulfate, N2S2O7); if the acid ends in -ous, the corresponding salt ends in -ite (pyrophosphorous acid, H4P2O5, potassium pyrophosphite, K4P2O5). Also,pyr-.