A rocky planet or terrestrial planet or telluric planet is a planet of mostly rock (e.g., silicates), such as Mercury, Venus, Mars or Earth. Among extra-solar planets, there are also larger such planets, such as those termed super-Earths and mega-Earths.
There is a presumed (and real?) correlation between planets being rocky and the amount of received electromagnetic radiation and stellar wind from the host star, thus how close they are to the star. A very thick atmosphere as per a gas giant would not last if the planet were too close (photoevaporation).
There is presumed to be something of an upper limit on the size of rocky planets.