Nonterrestrial

Nonterrestrial is an adjective used to describe anything not belonging to Earth or not occurring on Earth. It can refer to objects, environments, or phenomena outside the Earth's surface or atmosphere, including planets, moons, asteroids, and interplanetary space. The term is primarily used in scientific, educational, and public discourse to contrast with terrestrial.

In astronomy and space exploration, nonterrestrial often serves as a broad umbrella term for all space-related phenomena and bodies. In astrobiology and science fiction, it is used when discussing life, habitats, or biosignatures that would originate beyond Earth. In policy and law, the term appears less commonly, with more specific terms such as extraterrestrial or space-based assets preferred.

Etymology: from non- + terrestrial, with terrestrial derived from Latin terra earth. The term is neutral and non-prescriptive, intended to avoid assuming Earth-centered perspectives.

See also: extraterrestrial, celestial, space.