Pronunciation: (sOO"pur-fos'fāt),[key] —n.Chem. 1. Also called acid phosphate. a mixture of calcium acid phosphate and calcium sulfate prepared by treating phosphate rock with sulfuric acid: used chiefly as a fertilizer.
2. Also called triple superphosphate. a mixture prepared with phosphoric acid and containing about 45 percent of soluble phosphates, used as a fertilizer.