A missile is a weapon that flies through the air to hit a distant target. Unlike a bullet fired from a gun, which follows a simple arc, a missile can steer itself toward its target using guidance systems, kind of like a remote-controlled airplane.

Modern missiles use technologies like radar, GPS, or heat-seeking sensors to track and hit their targets, even if those targets are moving. A cruise missile flies low and fast like a jet airplane, while a ballistic missile rockets high into the atmosphere before falling back down toward its target. Some missiles are small enough to be carried by a soldier, while others are enormous rockets launched from ships or underground silos.

In earlier times, people used missile more broadly to describe anything thrown or launched as a weapon: arrows, spears, or stones. Today, though, the word almost always refers to self-propelled, guided weapons.

You might hear about anti-aircraft missiles designed to shoot down aircraft, or intercontinental ballistic missiles that can travel thousands of miles. Nations spend enormous resources developing and defending against missiles because of their power and range.