List of planets
In 2006, the International Astronomical Union (IAU) convened a Planet Definition Committee, deliberated, and ultimately reached a consensus on a new definition of a planet which leaves us with the eight planets we today consider to comprise the Solar System (thus the exit of Pluto).  That new definition: " A “planet” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit [meaning: 'there are no other bodies in its path that it must sweep up as it goes around the Sun'.]"