alien

alien, hypothetical intelligent extraterrestrial being. See extraterrestrial intelligence. See also extraterrestrial life; unidentified flying object.

This article was most recently revised and updated by Erik Gregersen.

Citation Information

Article Title: alien

Website Name: Encyclopaedia Britannica

Publisher: Encyclopaedia Britannica, Inc.

Date Published: 27 March 2025

Access Date: April 21, 2025