A crossbow is a ranged weapon using an elastic launching device similar to a bow; it consists of a bow-like assembly called a prod, mounted horizontally on a main frame called a tiller, which is hand-held in a similar fashion to the stock of a long gun. Crossbows shoot arrow-like projectiles called bolts or quarrels. The medieval European crossbow was called by many names, including crossbow itself; most of these names derived from the word ballista, an ancient Greek torsion siege engine similar in appearance