Orbital Weapon Platform
An Orbital Weapons Platform is any artificial satellite equipped with weapons of mass destruction, in orbit around an inhabited planet or suspended above a flat world. They are divisible broadly by function.
Military Deterrent/Tyranny
This kind of O.W.P. is put into place with its weapons toward the ground. In the event of any misbehavior on the part of the inhabitants (or disobedience to the authority), these weapons can be fired, and some chosen target destroyed instantly. Such targets include cities, landmarks, or patches of open ground. The Origin Satellite is an example.
Planetary Defense
This kind of O.W.P. is put into place with its weapons toward the sky. In the event of an incoming meteorite (or an invasion by aliens), these weapons can be fired, and some chosen target destroyed instantly. Such targets include meteorites, hostile missiles, and invading spaceships.
Armament
Any kind of projectile can be part of an O.W.P.: the range extends from tiny pellet-shot (which, in vacuo, can tear an invading spaceship open) to huge, powerful rockets and L.A.S.E.R.s.