Source : Webster's Revised Unabridged Dictionary (1913)

Hostler \Hos"tler\, n. [OE. hosteler, osteler, innkeeper, OF.
   hostelier, F. h[^o]telier. See {Hostel}, and cf.
   {Hospitaler}, {Hosteler}.]
   1. An innkeeper. [Obs.] See {Hosteler}.

   2. The person who has the care of horses at an inn or stable;
      hence, any one who takes care of horses; a groom; -- so
      called because the innkeeper formerly attended to this
      duty in person.

   3. (Railroad) The person who takes charge of a locomotive
      when it is left by the engineer after a trip.

Source : WordNet®

hostler
     n : someone employed in a stable to take care of the horses
         [syn: {stableman}, {stableboy}, {groom}, {ostler}]