Source : Webster's Revised Unabridged Dictionary (1913)

Tracker \Track"er\, n.
   1. One who, or that which, tracks or pursues, as a man or dog
      that follows game.

            And of the trackers of the deer Scarce half the
            lessening pack was near.              --Sir W.
                                                  Scott.

   2. (Mus.) In the organ, a light strip of wood connecting (in
      path) a key and a pallet, to communicate motion by
      pulling.

Source : WordNet®

tracker
     n : someone who tracks down game