as the title points out I will write today about meteors, meteorites, meteoroids and asteroids. I have to say that before I searched it was not sure which one is which.
Lets start with asteroid.
These things are the largest. You probably know few of them because the biggest are also called minor planets or dwarf planets. There are quite lot of them, the biggest one inside of the orbit of Neptune is Ceres, that is the dwarf planet with these cool bright spots. There are quite few types based on what are they composed of. There are carbonate, silicate and metallic asteroids for example.
Lot of them are also in the Kuiper belt.
This one is a bit tricky. It is smaller asteroid, sometimes just a dust. The important thing is that as well as asteroid it has to be flying in outer space to be itself. Of course there are millions and millions of these objects. Usually they are considered to be smaller than one meter. When such object enters the atmosphere it can be fast as 20 km/s!
Meteor is more often known as “shooting/falling star”. It is just the event when meteoroid enters the atmosphere and heats quickly since as I said it is pretty fast. In some time of the year Earth goes through dust that was left by comets. Those are called meteor showers. When meteor shines bright enough, more than any planet in the night sky, it is considered fireball, which was for example Chelyabinsk meteor.
Meteorite is object that survives the path through atmosphere and impacts Earth (or other object, Mars or Moon for example). Of course quite often these things shatter a lot. People are than trying to find the debris. Also some are quite dangerous and can easily kill person even if they are very small. The largest one piece has stunning 60 tonnes.