Quote Originally Posted by Man About Town View Post
A rocket is something that is propelled by a rocket engine and sometimes used to carry some cargo, including warheads.
A missile is something that is designed to hit a target, and not necessarily propelled by a rocket engine.
I think this is a good explanation of the difference (except that I added the word "sometimes" to the definition of rocket -- it depends on whether you consider the color-producing chemicals in a firework to be "cargo" or not). But I totally agree that "missile" implies the existence of a target.