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, H 4 Sb 2 O 7 , pyroarsenic, H 4 AS 2 O 7 , and pyrosulfuric, H 2 S 2 O 7 , 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, H 2 B 4 O 7 , and potassium pyrobate, K 2 B 4 O 7 , or pyrosulfuric, H 2 S 2 O 7 , and pyrosulfate, N 2 S 2 O 7 ); if the acid ends in -ous, the corresponding salt ends in -ite ( pyrophosphorous acid, H 4 P 2 O 5 , potassium pyrophosphite, K 4 P 2 O 5 ).
Also, pyr- .
[ pyro-, comb. form of pyr FIRE ]