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 other cases such as science fiction, conspiracy theory and new-age discourse to denote extraterrestrial
beings. The term can be used in a broader manner to refer to any object or concept. As an adjective it can be used to describe
something foreign or something so different as to be incomprehensible or incompatible.