traverser

from WordNet (r) 3.0 (2006)

traverser
    n 1: someone who moves or passes across; "the traversers slowly
         ascended the mountain"

from The Collaborative International Dictionary of English v.0.48

Traverser \Trav"ers*er\, n.
   1. One who, or that which, traverses, or moves, as an index
      on a scale, and the like.
      [1913 Webster]

   2. (Law) One who traverses, or denies.
      [1913 Webster]

   3. (Railroad) A traverse table. See under {Traverse}, n.
      [1913 Webster]