1. The path of one body in space around another body; such as, the orbit of the earth around the sun, or the moon around the earth.

When the two bodies are similar in mass, as in a binary star, both bodies move around their common center of mass.

The movement of objects in orbit follow Johann Kepler's laws, which apply to artificial satellites as well as to natural bodies.

2. The path followed by one object around another as a result of their mutual gravitational interaction.

As a result of the inverse square law of gravitation, planetary orbits are approximately conic sections.

A satellite whose orbital period around the central body is the same as the rotation period that the central body has a synchronous orbit.