A crossbow is a weapon that shoots arrows using a bow mounted sideways on a wooden or metal frame, with a trigger mechanism to release the string. Unlike a regular bow that you hold vertically and pull back with muscle power each time, a crossbow lets you lock the string in place and shoot with a simple trigger pull, like a rifle.

Crossbows were invented in ancient China and became powerful military weapons in medieval Europe. They were easier to learn than traditional bows: an archer needed years of training to use a longbow effectively, but a soldier could learn to shoot a crossbow in a few days. This made crossbows especially valuable in warfare, though they were slower to reload than regular bows.

The crossbow's power came from its mechanical advantage. The string could be drawn back using a crank or lever, storing more energy than most people could hold with their arms alone. This let crossbows pierce armor that might stop regular arrows. Today, people use crossbows for hunting and target shooting, and they appear often in historical movies and fantasy games.