Sulphacid \Sulph*ac"id\, n. [Sulpho- + acid.] (Chem.)
An acid in which, to a greater or less extent, sulphur plays
a part analogous to that of oxygen in an oxyacid; thus,
thiosulphuric and sulpharsenic acids are sulphacids; --
called also {sulphoacid}. See the Note under {Acid}, n., 2.
[1913 Webster]