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]