Planet
A planet is a body made of matter that orbits the Sun. A similar body orbiting another star is an exoplanet.
The International Astronomical Union recently clarified the definition. A planet must orbit the Sun not another planet; it must be so massive that gravity has forced it into a near-spherical shape and it must have cleared its vicinity of other bodies orbiting the Sun. As a result of this clarification, Pluto, hitherto regarded as a planet, has been demoted. The bodies still recognised as planets are (in increasing distance from the Sun):