"A planet is a large astronomical body that is neither a star nor a stellar remnant. There are competing scientific definitions of a ´planet´. In the dynamicist definition adopted by the International Astronomical Union (IAU), a planet is a non-stellar body that is massive enough to be rounded by its own gravity, that directly orbits a star, and that has cleared its orbital zone of competing objects. The IAU has also declared that there are eight planets in the Solar System, independently of the formal definition.[a] In the geological definition used by most planetologists, a planet is a rounded sub-stellar body, possibly a satellite. In addition to the eight Solar planets accepted by the IAU, these include dwarf planets such as Eris and Pluto and planetary-mass moons. Bodies meeting the geological definition are sometimes called "planetary-mass objects" or "planemos" for short." - (en.wikipedia.org 26.02.2022)
en