Despite common misconceptions, these space phenomena are different from each other. An asteroid is a small solar system body in orbit around the Sun, which are sometimes referred to or classed as minor planets. A meteoroid, however, is a sand-to-boulder-sized particle of debris drifting through space in orbit around the Sun or other bodies.
Finally, comets are ice-based small solar system bodies that when close to the Sun display a visible coma (a nebulous temporary atmosphere) and tail of ice, dust and rock particles. Comets, unlike asteroids, generally originate in the outer solar system.