Function: noun
Date: 1784
1 : a syrupy or deliquescent tribasic acid H 3 PO 4 used especially in preparing phosphates (as for fertilizers), in rust-proofing metals, and especially formerly as a flavoring in soft drinks ― called also orthophosphoric acid
2 : a compound (as pyrophosphoric acid or metaphosphoric acid) consisting of phosphate groups linked directly to each other by oxygen