A
terrestrial planet,
telluric planet or
rocky planet is a
planet that is composed primarily of
silicate rocks or
metals. Within the
Solar System, the terrestrial planets are the
inner planets closest to the
Sun, i.e.
Mercury,
Venus,
Earth, and
Mars. The terms "terrestrial planet" and "telluric planet" are derived from
Latin words for
Earth (
Terra and
Tellus), as these planets are, in terms of composition, "Earth-like".