When it enters a planet's atmosphere is meteor. Any piece remaining after impact is a meteorite.
Explanation:
There is often confusion when it comes to the terms asteroid, meteoroid, meteor, and meteorite. To most people it seems as if it is the same thing, but there are some defining differences between them, and when do they change, thus getting another term.
The asteroids and meteoroids are rocky bodies in space that circle around a star, with the asteroids being larger and the meteoroids being smaller.
When they enter Earth's atmosphere and start vaporizing they become meteors. They have a glowing appearance for few seconds, and people often call them shooting stars.
If a piece of any size manages to remain after its passing through the atmosphere and has an impact with Earth's surface than it is called meteorite. The size can vary a lot, from tiny pebble, to few square meters, or even few square km in extreme cases.
