Superphosphate \Su`per*phos"phate\, n. (Chem.)
An acid phosphate.
[1913 Webster]
{Superphosphate of lime} (Com. Chem.), a fertilizer obtained
by trating bone dust, bone black, or phosphorite with
sulphuric acid, whereby the insoluble neutral calcium
phosphate, {Ca3(PO4)2}, is changed to the primary or acid
calcium phosphate {Ca(H2PO4)2}, which is soluble and
therefore available for the soil.
[1913 Webster]