Earth
Earth's shape is a spheroid: not quite a sphere because it is slightly squashed on the top and bottom. The shape is called an oblate spheroid. As Earth spins around itself, centrifugal force forces the equator out a little and pulls the poles in a little. The equator, around the middle of Earth's surface, is about  long. The reason the Earth is roughly a sphere (and so are all planets and stars) is gravity. Meteorites, on the other hand may be any shape because, in their case, the force of gravity is too weak to change their shape.