A cruise missile is a guided missile that flies, through the atmosphere, to its target. It can be launched from an airplane, a ship, a submarine, or a surface vehicle. The missile relies on both aerodynamic lift and engine propulsion to stay airborne, and primarily uses aerodynamic control surfaces to change its course.
The first operational cruise missile was the WWII German V-1, which had quite primitive propulsion: it kept on a straight-line course, and, when a timer expired, went into a dive that took it into a target -- or the ground. The V-1 did not sense its target, but used the GOLIS principle: go-onto-location-in-space. Later in the war, the manned kamikaze was a foretaste of the automated anti-shipping cruise missile, which had guidance that could follow a GOT paradigm: go-onto-target.
More modern GOT cruise missiles, which can hit moving targets, have automated final guidance, such as anti-shipping missiles that have a search radar, or anti-radiation missiles that home on a radar or other electromagnetic signal.
Cruise missiles have a variety of warheads, including a single high-explosive (i.e., unitary) or nuclear warhead. All U.S. nuclear-capable cruise missiles use the W80 warhead of 5 or 150 kiloton selectable yield. They may release various kinds of cluster submunitions, including anti-tank, anti-personnel, chemical or biological weapon dispensers, or carbon filaments to short out electrical systems.
Modern cruise missiles may use inertial or GPS guidance when flying at rellatively high altitude. Some use terrain contour mapping (TERCOM) radar, which literally follows a topographic map, using compass bearings and a radio altimeter.
They may be air-launched, such as the U.S. AGM-86 ALCM or Russian Raduga KSR-5 (NATO reporting designation AS-6 KINGFISH), or launched from ships and submarines, such as the Russian P-700 GRANIT (NATO reporting designationSS-N-19 SHIPWRECK) or U.S. BGM-109 Tomahawk.