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

• In broadcasting terrestrial indicates that TV or radio signals are received through a conventional aerial. See terrestrial television.

Terrestrial television is a term which refers to modes of television broadcasting which do not involve satellite transmission.

• In communication networking, "terrestrial" indicates signals travelling through fiber optic cable or copper wire, usually located underground or undersea.
• In space exploration, "terrestrial" indicates materials or objects of Earthly origin, as opposed to, for example, meteorites that are found on the Earth but originated elsewhere in the solar system.