crossbow

from WordNet (r) 3.0 (2006)

crossbow
    n 1: a bow fixed transversely on a wooden stock grooved to
         direct the arrow (quarrel)

from The Collaborative International Dictionary of English v.0.48

Crossbow \Cross"bow`\ (kr[o^]s"b[=o]`), n. (Archery)
   A weapon, used in discharging arrows or bolts, formed by
   placing a bow crosswise on a stock.
   [1913 Webster]