Terrestrial literally means 'of the earth' and is used in a variety of contexts:

• In biology and in the general sense, terrestrial means indicates ground-dwelling (compare aquatic). See land.
• In broadcasting terrestrial indicates that TV or radio signals are received through a conventional aerial. See terrestrial television.
• In communication networking, "terrestrial" indicates signals travelling through fiber optic cable or copper wire, usually located underground or undersea.
• In astronomy, terrestrial can refer to the first four planets in the solar system - planets with a rocky exterior.
• Terrestrial may also be used in contrast to extra-terrestrial, indicating anything of Earth-origin rather than from outer space.