Any interplanetary particle or chunk of stony or metallic matter (meteoroid) that survives passage through Earth's atmosphere and strikes the ground or that reaches the surface of another planet or moon.
On Earth the speed of entry
at least 7 mi/second (11 km/second)
generates enough friction with the air to vaporize part or all of the meteoroid and produce a streak of light ( meteor ). Though vast numbers of meteoroids enter Earth's atmosphere each year, only a few hundred reach the ground.