Meteoroids

Technical clarification:
* Meteoroid - sand to boulder-sized extraterrestrial matter, regardless of composition, location or visibility.
* Meteor - visible part of meteoroid having entered atmosphere, generally the flaming tail, not the object itself. Commonly meteoroids are referred to as meteors despite this.
* Meteorite - meteoroid that has impacted with the ground and survived it.

Comet is a very specific type of asteroid and somewhat unrelated to meteoroids.

Related:
* Asteroids - the mid point extraterrestrial matter that's larger than a meteoroid but smaller than a planet(oid).