Meaning of superphosphate

su•per•phos•phate

Pronunciation: (s"pur-fos'fāt), [key]
— n. Chem.
  1. Also calleda mixture of calcium acid phosphate and calcium sulfate prepared by treating phosphate rock with sulfuric acid: used chiefly as a fertilizer.
  2. Also calleda mixture prepared with phosphoric acid and containing about 45 percent of soluble phosphates, used as a fertilizer.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.