Aliens are foreigners to their surroundings. The word is commonly used in law to denote non-citizens of the country of their whereabouts, and in fiction to denote extraterrestrial beings. The usage of the term is not limited to humans.
Table of contents [showhide] 1 Biology 2 Fiction and conspiracies 3 Law 4 Computing 4.1 External link 5 Dictionary
Biology In biology the adjective alien, as in alien species, means that the normal local is somewhere else, that a species or specimen exceptionally has been established in the area in question. Words with similar meaning in biology include exotic, adventive, introduced, and naturalized. These terms contrast with terms as indigenous and endemic.
Fiction and conspiracies In popular fiction and conspiracy theories, alien is a term that is often used to refer to life forms, especially intelligent life forms, that are of extraterrestrial origin, i.e. not coming from the Earth. Prime examples of how aliens are viewed are found in the movies Alien, E.T., Signs, and Independence Day. A peculiarity of this usage is its ethnocentricity: when humans in fictional accounts accomplish interstellar travel and land on a planet elsewhere in the universe, the local inhabitants of these other planets are usually still referred to as "alien," even though they are the native life form and the humans are the intruders. This may be seen as a reversion to the classic meaning of "alien" as referring to "other," in contrast to "us" in the context of the writer's frame of reference.
Law In law, an alien is a foreigner who is not a citizen of the land in which he lives. If they live there, as opposed to being just a visitor, they may be called a "resident alien".
