/awr"thoh fos fawr"ik, -for"-, awr'-/ , Chem.
a colorless, crystalline solid, H 3 PO 4 , the tribasic acid of pentavalent phosphorus: used chiefly in fertilizers, as a source of phosphorus salts, and in soft drinks as an acidulant and flavoring agent.
[ 1870-75; ORTHO- + PHOSPHORIC ACID ]