Webster’s Revised Unabridged Dictionary · 1913
Hydrosulphide
Hy′dro·sul′phide, n. (Chem.) One of a series of compounds, derived from hydrogen sulphide by the replacement of half its hydrogen by a base or basic radical; as, potassium hydrosulphide, KSH. The hydrosulphides are analogous to the hydrates and include the mercaptans.