What is the difference between asteroids, comets, and meteors?

Asteroids are small heavenly bodies, which move around the sun like the planets. Thus, they are also called planetoids. Most of them go around the sun in the aste roid belt. Even comets, like Halley's comet, which has been sighted many times in the sky, are small heavenly bodies. They are characterized by a different orbit and a bright glowing tail. 

Meteorites are cosmic chunks of rock. When they enter the atmosphere, impact pressure causes the body to heat up and emit light, thus forming a fireball, also known as a meteor or shooting/falling star. They may occur very frequently.