The catapult is a siege weapon that can hurl very heavy objects over long distances wreaking havoc in the enemy ranks. This device was widely used during medieval wars, or siege stronghold. Although very imprecise catapults proved very effective and inspired fear among the enemy troops.

There are several types and variations of the catapult. First there is the ballista, which uses leverage to throw imposing round objects such as rocks or large cast iron balls with a huge spatula. The trebuchet works like a giant sling that can throw balls weighting over 100 kg at more than 200 meters away. There is also the large crossbow, which like its smaller counterpart, throws arrows, but of greater size, and able to skewer a whole row of knights at once.

This kind of siege weapons can now be found in heroic fantasy movies and games during major battles where dwarves, elves, orcs and other fantastic creatures engage in epic battles. Nearly all catapults employed in ancient and medieval artillery operated by a sudden release of tension on wooden beams or twisted cords of horsehair, gut, sinew, or other fibres. An exception was the medieval trebuchet, powered by a counterweight.

Later, larger catapults mounted on a single arm also hurled stones, pots of boiling oil, and incendiaries at a high trajectory. They were used to attack or defend fortifications. Catapults were widely employed in siege warfare, but with the introduction of artillery they passed from use. Modern mechanisms using steam, hydraulic pressure, tension, or other force to launch gliders, aircraft, or missiles are also called catapults.