[eyl-yuhn, ey-lee-uhn]



Origin of alien

1300–50; Middle English < Middle French < Latin aliēnus, equivalent to *alies- (ali-, base of alius other + -es- noun suffix) + -nus adj. suffix
Related formsnon·al·ien, noun, adjectivepro·al·ien, adjective

Synonyms for alien

1. immigrant. 2. See stranger. 3. outcast. 7. exotic, foreign.

Usage note Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for alien

Contemporary Examples of alien

Historical Examples of alien

  • Let me tell you, Mr. Cross, we are really in an alien country here.

    In the Valley

    Harold Frederic

  • It had carried an alien note that overcame him with instinctive fear and horror.

    Salvage in Space

    John Stewart Williamson

  • They were quiet for a while, and then Marsh turned to Henry and said, "Is that alien to you?"

    Changing Winds

    St. John G. Ervine

  • At Rumpell's and at Boveyhayne he had had no sensation of alien origin.

    Changing Winds

    St. John G. Ervine

  • His sense of being an alien in Dublin had persisted all the time that he had lived there.

    Changing Winds

    St. John G. Ervine

British Dictionary definitions for alien



a person owing allegiance to a country other than that in which he lives; foreigner
any being or thing foreign to the environment in which it now exists
(in science fiction) a being from another world, sometimes specifically an extraterrestrial


unnaturalized; foreign
having foreign allegiancealien territory
unfamiliar; strangean alien quality in a work of art
(postpositive and foll by to) repugnant or opposed (to)war is alien to his philosophy
(in science fiction) of or from another world


(tr) rare to transfer (property, etc) to another
Derived Formsalienage (ˈeɪljənɪdʒ, ˈeɪlɪə-), noun

Word Origin for alien

C14: from Latin aliēnus foreign, from alius other
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for alien

mid-14c., "strange, foreign," from Old French alien "alien, strange, foreign; an alien, stranger, foreigner," from Latin alienus "of or belonging to another, foreign, alien, strange," also, as a noun, "a stranger, foreigner," adjectival form of alius "(an)other" (see alias). Meaning "not of the Earth" first recorded 1920. An alien priory (c.1500) is one owing obedience to a mother abbey in a foreign country.


"foreigner, citizen of a foreign land," from alien (adj.). In the science fiction sense, from 1953.

Online Etymology Dictionary, © 2010 Douglas Harper

alien in Science



Introduced to a region deliberately or accidentally by humans. Starlings, German cockroaches, and dandelions are species that are alien to North America but have become widely naturalized in the continent. Compare endemic indigenous.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.