Synonyms for Catapult (same or very similar meaning)
WordNet sense 1 (a plaything consisting of a Y-shaped stick with elastic between the arms; used to propel small stones):
sling, slingshot
WordNet sense 2 (a device that launches aircraft from a warship):
launcher
WordNet sense 3 (medieval artillery used during sieges; a heavy war engine for hurling large stones and other missiles):
mangonel, onager, bricole, arbalest, arbalist, ballista, trebuchet, trebucket
From the ODE community, based on WordNet
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