1) Ancient Greek artillery 2) Arrow type 
'Shield smasher'. torsion gun.
Literally, a shield smasher, this was a term used for those siege engines which used a torsion engine (tormentum) driving a vertical firing arm to hurl objects. This would include all versions of onagri. Also used as a generic term for all kinds of the mechanical artillery engines, that either hurled objects, such as bolders or fire pots, or shot b…...
(Latin) heavy-duty Roman crossbows that launched missiles that could cut through armor.