The term "alien" refers to a being from another planet or celestial body, often depicted in science fiction. These entities are typically characterized by their distinct physical features, advanced technology, and different cultures compared to humans. The concept of aliens has been popularized in movies, books, and television shows, sparking curiosity and imagination about life beyond Earth. In legal terms, an "alien" can also refer to a person who is not a citizen of the country in which they reside. This definition is often used in immigration law to describe individuals who may have different rights and responsibilities compared to citizens. The distinction between citizens and aliens is important in discussions about immigration policies and international relations.