Catapult

Catapult, any of various engines of war used in ancient and medieval times to discharge javelins, darts, rocks, and other missiles. The larger kinds were mounted on a strong wooden platform; the trigger or projector of a gigantic crossbow was drawn back by ropes and held by a catch. Another type of catapult employed the principle of torsion to hurl heavy stones or objects over walls and across moats, cords being twisted by winches to pull back the propelling mechanism. Smaller hand-carried catapults were also used. See Fortification and Siege Warfare.

In modern naval warfare, aircraft are catapulted from the deck of an aircraft carrier along a runner or track. The plane is propelled off the runner at flying speed by means of an explosive charge or by hydraulic or steam pressure.