Meteorites have their origin in outer space. They are relatively small pieces of dust and debris, usually left behind in the wake of a comet. Meteorites, that are huge in size, have their origin in space, as asteroids. They are left over pieces of matter from formation of the solar system, which could not clump together to form a planet like our Earth. There is a dense belt of such asteroids outside the orbit of the planet Mars, called the 'Asteroid Belt'. Asteroids are huge in size and their lengths can number to kilometers!
Once in a while, small pieces of rock or dust, come into range of Earth's gravitational pull and fall on Earth as shooting stars. An asteroid dislodged from its trajectory and falling on Earth is also called a meteorite. However, an asteroid being huge in size, causes a cataclysmic explosion on Earth on impact.
Origin
'Meteor' and 'Meteorite' facts are interchangeable terms and we shall see why they are so. When these rocks and pieces of dust are floating in space, they are called 'Meteoroids'. When they make a blazing entry into Earth's atmosphere, they are called 'Meteors'. Finally, if they survive the burning entry into Earth's atmosphere and fall on Earth, they are called 'Meteorites'. So a meteorite could originate from comet debris called meteoroids or larger objects called asteroids! Here are some basic facts about meteorites, meteors and meteoroids.
Comets leave tons of dust and debris in their trail as they travel along long orbits round the Sun. When Earth, while revolving around the Sun, passes through some patches of this comet debris, it enters the Earth's atmosphere