- Asteres planetai, ‘wandering stars’, for star-like objects which apparently moved over the sky, was the term employed by Greek astronomers.
- The term has included a variety of different objects, like the moon, satellites, sun, and asteroids.
- As per International Astronomical Union (IAU), a planet is a body that orbits the Sun, is massive enough for its own gravity to make it round, and has ‘cleared its neighbourhood’ of smaller objects approaching its orbit.