alien

[ ey-lee-uhn, eyl-yuhn ]
See synonyms for: alienaliens on Thesaurus.com

noun
  1. a creature from outer space; extraterrestrial.

  2. Often Disparaging and Offensive. a resident of one country who was born in or owes allegiance to another country and has not acquired citizenship by naturalization in the country of residence (distinguished from citizen). : See also resident alien, illegal alien.

  1. a foreigner.

  2. a person who has been estranged or excluded.

  3. a plant or animal species not originating where it is found but introduced, sometimes accidentally, from its native environment elsewhere: Imported plants, seeds, or bulbs may harbor unwanted aliens such as foreign insects or the seeds of other plants.

adjective
  1. unlike one's own; strange; not belonging to one: In English class, our teacher treated all slang as alien speech.

  2. residing under a government or in a country other than that of one's birth without having or obtaining the status of citizenship there.

  1. belonging or relating to noncitizens: Under certain conditions, seizure of alien property is authorized.

  2. opposed; adverse; hostile (usually followed by to or from): Their manifesto is full of ideas alien to modern thinking.

  3. (of a plant or animal species) not native; introduced from a different environment: The bullfrog is native to some Canadian provinces, but is an alien species in British Columbia.

Origin of alien

1
First recorded in 1300–50; Middle English, from Middle French, from Latin aliēnus “belonging to or affecting someone else; someone else's; not one's own; foreign,” equivalent to ali(us) “other” + -ēnus adjective suffix

usage note For alien

word story For alien

Other words for alien

Other words from alien

  • non·al·ien, noun, adjective
  • pro·al·ien, adjective

Words Nearby alien

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use alien in a sentence

British Dictionary definitions for alien

alien

/ (ˈeɪljən, ˈeɪlɪən) /


noun
  1. a person owing allegiance to a country other than that in which he lives; foreigner

  2. any being or thing foreign to the environment in which it now exists

  1. (in science fiction) a being from another world, sometimes specifically an extraterrestrial

adjective
  1. unnaturalized; foreign

  2. having foreign allegiance: alien territory

  1. unfamiliar; strange: an alien quality in a work of art

  2. (postpositive and foll by to) repugnant or opposed (to): war is alien to his philosophy

  3. (in science fiction) of or from another world

verb
  1. (tr) rare to transfer (property, etc) to another

Origin of alien

1
C14: from Latin aliēnus foreign, from alius other

Derived forms of alien

  • alienage (ˈeɪljənɪdʒ, ˈeɪlɪə-), noun

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

Scientific definitions for alien

alien

[ ālē-ən ]


  1. 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.