terrestrial planet - a planet having a compact rocky surface like the Earth's; the four innermost planets in the solar systemEarth, globe, world - the 3rd planet from the sun; the planet on which we live; "the Earth moves around the sun"; "he sailed around the world" inferior planet - any of the planets whose orbit lies inside the earth's orbit planet - any of the celestial bodies (other than comets or satellites) that revolve around the sun in the solar system |