Terrestrial planet

The terrestrial planets are the four planets in our solar system that are closest to the sun: Mercury, Venus, Earth, and Mars. The terrestrial planets are solid, spherical, and (except for Mercury) enveloped by atmosphere. The Earth is the largest of these and is the only one known to support life.

The term derives from the Latin word for Earth, terra. It is used to describe planetary bodies which have a size, shape, and composition similar to those of Earth.