Definition of alien in English:

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Pronunciation: /ˈālēən/


1Belonging to a foreign country or nation.
Example sentences
  • This is blundering on foreign soil in an alien culture which they fail to grasp and arrogantly underestimate and they will ultimately pay the price of their ignorance.
  • Despite numerous campaigns among players and fans to try and tackle racism, the game is still submerged in a sea of stereotypes about foreigners and alien cultures.
  • For right-wing politicians, this commodification is associated with an invasive, alien, foreign culture.
1.1Unfamiliar and disturbing or distasteful: bossing anyone around was alien to him they found the world of adult education a little alien
More example sentences
  • Perhaps it might seem alien to someone unfamiliar with comics.
  • By forming this non-political movement, the members would not be made strange or alien to power.
  • In fact, the whole act of writing anything at all feels rather strange and alien to me now.
unfamiliar, unknown, strange, peculiar;
exotic, foreign
incompatible with, unusual for, opposed to, conflicting with, contrary to, in conflict with, at variance with, out of step with
rare oppugnant to
1.2 [attributive] Relating to or denoting beings supposedly from other worlds; extraterrestrial: an alien spacecraft
More example sentences
  • King's program didn't merely advance the notion that an alien spacecraft crashed at Roswell in 1947.
  • One third accepted lucky numbers and 30 percent felt that some UFOs were alien spacecraft.
  • The inner workings of alien spacecraft are at last revealed!
extraterrestrial, unearthly, otherworldly;
Martian, Jovian, Venutian
1.3(Of a plant or animal species) introduced from another country and later naturalized.
Example sentences
  • The controversy over trout introductions has come to focus much of the current awareness on the impact of alien species both plant and animal.
  • In this context the issue of alien plant and animal species becomes problematic.
  • He urged gardeners to avoid the use of exotic plants and not to plant alien flowers out in the wild or along hedgerows.


1A foreigner, especially one who is not a naturalized citizen of the country where they are living: an illegal alien
More example sentences
  • Because he's actually not a citizen, but an illegal alien, Valle is now detained in preparation for deportation.
  • It would also make it harder for illegal aliens to seek political asylum.
  • One assumes it's a sincere position against illegal aliens and illegal immigration.
foreigner, nonnative, immigrant, emigrant, émigré
1.1A hypothetical or fictional being from another world.
Example sentences
  • Reading that he thinks aliens in spaceships brought the DNA that humans came from to earth was enough.
  • Go there and see an awe-inspiring picture of one of the original aliens in its spaceship.
  • The novel follows the journey of a small group of people who leave our solar system to make contact with these newly discovered aliens.
extraterrestrial, ET;
Martian, Jovian, Venutian
informal little green man
1.2A plant or animal species originally introduced from another country and later naturalized.
Example sentences
  • They caution that the impact of these aliens on other marine life has yet to be established.
  • Invasive aliens, mainly weeping willows, which are the dominant species at the dam, were eradicated.
  • These aliens created too much shade for prairie plants that need full sunlight to survive.



Example sentences
  • I've always been fascinated by the mix of alienness and similarity one finds in the leaders of countries like Iraq - really across what we used to call the Third World.
  • The film asks us to see our own planet as an alien planet, and to look again at the unconquerable alienness of other people, at the enigma of absence and presence, death and life.
  • My great interest in Anglo-Indian contact in that period was the profound alienness of each group in the eyes of the other.


Middle English: via Old French from Latin alienus 'belonging to another', from alius 'other'.

  • The word came via Old French from Latin alienus ‘belonging to another’, from alius ‘other’. It was initially used for foreigners, but since the 1950s has mostly been used for beings from another planet. From the same base is early 16th-century alienate and alienation (Late Middle English). The theatrical phrase alienation effect dates from the 1940s and is a translation of German Verfremdungseffekt.

Words that rhyme with alien

Australian, bacchanalian, Castalian, Deucalion, episcopalian, Hegelian, madrigalian, mammalian, Pygmalion, Salian, saturnalian, sesquipedalian, tatterdemalion, Thessalian, Westphalian

For editors and proofreaders

Syllabification: a·li·en

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