A catapult is any one of a number of non-handheld mechanical devices used to throw a projectile a great distance without the aid of an explosive substance—particularly various types of ancient and medieval siege engines.

The name is the Latinized form of the Ancient Greek - katapeltes, from - kata (downwards, into, against) and - pallo (to poise or sway a missile before it is thrown). The catapult appears to have been invented in 399 BC in the city of Syracuse during the reign of the tyrant Dionysius I. Originally, "catapult" referred to a dart-thrower, while "ballista" referred to a stone-thrower, but the two terms swapped meaning sometime in the fourth century AD.

A siege engine is a device that is designed to break or circumvent city walls and other fortifications in siege warfare.

The earliest engine was the battering ram, developed by the Assyrians, followed by the catapult in ancient Greece. The Spartans used battering rams in the Siege of Plataea in 429 BC, but it seems that the Greeks limited their use of siege engines to assault ladders, though Peloponnesian forces used something resembling flamethrowers.

The last large-scale military use of catapults was during the trench warfare of World War I. During the early stages of the war, catapults were used to throw hand grenades across no man's land into enemy trenches. These were eventually replaced by small mortars.

Also, are used to launch aircraft carriers into the air because the launch pad is too short. Ships also use them to drop bombs on submairnes.

Small catapults, referred to as traps are still widely used to launch Clay targets into the air in the sport of Clay pigeon shooting.

Until recently, in England, catapults were used by thrill-seekers to experience being catapulted through the air. The practice has been discontinued due to fatalities, when the participants failed to land onto the safety net.

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