Source : Webster's Revised Unabridged Dictionary (1913)

Mercaptan \Mer*cap"tan\, n. [F., fr. NL. mercurius mercury + L.
   captans, p. pr. of captare to seize, v. intens. fr. capere.]
   (Chem.)
   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.