Meteorite, meteor, and meteoroid describe the same rocky object at different stages of its journey. A meteoroid is a small piece of rock or metal traveling through space. When it enters Earth's atmosphere and burns up as a streak of light, it becomes a meteor (commonly called a shooting star). If part of it survives the fiery passage and reaches the ground, that fragment is called a meteorite. An asteroid is much larger — typically hundreds of meters or more across — and orbits the Sun like a small planet. 'Space rock' is an informal umbrella term for any of these. For example: 'We saw a meteor flash across the sky, and the next morning a farmer found a meteorite in his cornfield.'
From Greek 'meteōron' (something high up in the air) and the English suffix '-ite' (used for rocks and minerals). The word was created in the early 1800s to name space rocks that reach the ground, distinguishing them from meteors that burn up in the atmosphere.