(inorganic chemistry) Any salt or ester of pyrophosphoric acid.

plural of pyrophosphate

(biochemistry) A pentose phosphate, formed from ribose 5-phosphate by the enzyme ribose-phosphate diphosphokinase, which plays a role in transferring phospho-ribose groups in several reactions.

(medicine) A medical condition, also called pseudogout or CPPD, which resembles gout but results from precipitation of crystals in the joints by a different compound.