/sooh'peuhr fos"fayt/ , 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.
[ 1790-1800; SUPER- + PHOSPHATE ]