ar·ba·lest also ar·ba·list (är'bə-lĭst) n. A medieval missile launcher designed on the principle of the crossbow.
[Middle English arblast, from Old English, from Old French arbaleste, from Late Latin arcuballista : Latin arcus, bow + Latin ballista, ballista; see ballista.] ar'ba·lest'er (-lěs'tər) n.
"crossbow," c.1100, from O.Fr. arbaleste, from V.L. arbalista, from L.L. arcuballista "catapult," from L. arcus "bow" (see arc) + ballista "machine for throwing projectiles" (see ballistic).