From Greek 'katapeltes,' from 'kata-' (against) + 'pallein' (to hurl) — literally 'a hurler-against.'
A military machine for hurling large stones or other missiles; also, a device used to launch an aircraft from the deck of a ship.
From Latin catapulta, from Greek katapéltēs (καταπέλτης), composed of kata- (κατά, down upon, against) + pallein (πάλλειν, to hurl, to brandish, to swing), from PIE *pel-h₂- (to swing, to shake, to drive). The literal meaning is 'a hurler-against' or 'that which hurls down upon' — a siege engine designed to fling projectiles over or against fortification walls. The Greek pallein is related to pállos (a lot cast by shaking), and the same PIE root *pel-h₂- may underlie Latin pellere (to drive, to push, whence compel, expel, pulse, repel) and Greek pólemos (war, literally 'a shaking'). The word
The Greek prefix 'kata-' (down, against) that begins 'catapult' also begins 'catastrophe' (an overturning), 'cataclysm' (a washing down), 'catalyst' (a loosening down), and 'catatonic' (a stretching down) -- making 'kata-' one of Greek's most destructive prefixes, almost always implying something forcefully descending or coming apart.