Any one of series of compounds, hydrosulphides of
   alcohol radicals, in composition resembling the alcohols, but
   containing sulphur in place of oxygen, and hence called also the
   sulphur alcohols. In general, they are colorless liquids having a
   strong, repulsive, garlic odor. The name is specifically applied to
   ethyl mercaptan, C2H5SH. So called from its avidity for mercury, and
   other metals.