DictionaryAI

alien

AY-lee-uhn/ˈeɪ.li.ən/

Pluralaliens

9 meanings of alien

Practice

  1. 1
    creature from spacenouncountable
    A living being that comes from another planet or another dimension.

    The film imagines an alien arriving from a distant galaxy.

    Witnesses claimed an alien stepped out of the glowing craft.

    Similarextraterrestrial

  2. 2
    extraterrestrialadjective
    Relating to extraterrestrial life, or typical of a creature from another planet.

    The probe returned images of an alien landscape unlike anything on Earth.

    Fans argued about whether the creature's biology was genuinely alien.

    Similarextraterrestrial

    Oppositeterrestrial, earthly

  3. 3
    unfamiliaradjective
    Completely unfamiliar, strange, or far removed from one's own experience.

    The idea of living alone was completely alien to someone raised in a crowded household.

    After a decade abroad, his old neighborhood felt strangely alien.

    UsageUsually alien to someone or something: the idea was alien to him.

    Similarstrange, weird, bizarre, abnormal, unfamiliar

    Oppositefamiliar

    Note

    When a person follows to, as in alien to her, it names who finds the thing unfamiliar. When a belief or value follows, as in principles alien to our faith, the effect is stronger than "unfamiliar" and comes closer to "incompatible." Without to, the word describes a quality felt as strange, as when Wordsworth hears "an alien sound of melancholy" in The Prelude (1850).

  4. 4
    foreign citizennouncountable
    A person who is a citizen or national of another country; sometimes used with contempt for foreigners seen as untrustworthy.

    Resident aliens must report their income to the tax authorities.

    The new law changed how an alien can apply for permanent residence.

    UsageMostly an official word, as in resident alien; in everyday talk foreigner or immigrant is usual.

    Similarforeigner, noncitizen

    Oppositecitizen, national

    Note

    Law's word for the foreigner. Blackstone's Commentaries (1765) holds that an alien born may buy land but not keep it for his own use, since the king is entitled to it. In Cherokee Nation v. Georgia (1831), John Marshall records counsel's claim that the Cherokee were aliens owing no allegiance to the United States. Sting's "legal alien" in Englishman in New York borrows that official phrasing with a wry dignity.

    Checked 31 Oct 2026 · 5 facts

    • William Blackstone's Commentaries began publication in 1765; the relevant passage appears in Book the First. gutenberg.org
    • Blackstone says an alien born may purchase land but cannot retain it for his own use because the king becomes entitled to it. gutenberg.org
    • Cherokee Nation v. Georgia was decided in 1831, with John Marshall writing the majority opinion. en.wikipedia.org
    • Marshall reports counsel's argument that individual Cherokees were aliens owing no allegiance to the United States. denix.osd.mil
    • Sting's Englishman in New York includes the words "legal alien". sting.com
  5. 5
    from abroadadjective
    Belonging to another country or government rather than one's own; foreign.

    The treaty restricted alien ownership of farmland near the border.

    Voters worried about alien influence in their national elections.

    Similarforeign

    Oppositedomestic, native

  6. 6
    not nativenouncountable
    A person, animal, plant, or other thing that comes from outside the family, group, organization, or territory in question.

    Ecologists track how an alien spreads once it escapes into local waterways.

    In the close-knit firm, outside hires were quietly treated as aliens.

    Similaroutsider, stranger

    Oppositenative, insider

    Note

    Ecologists use it most in the phrase alien species, for plants and animals carried, often accidentally, into ecosystems where they do not belong. Here the word marks where something comes from, not how strange it looks. An alien weed can seem perfectly ordinary.

Less common meanings

  1. 7
    outcastnouncountable
    A person excluded from certain privileges, or one who has become estranged from others.

    Stripped of his membership, he lived as an alien at the edge of the community.

    The reforms left longtime supporters feeling like aliens in the party they had built.

    UsageOften an alien in a group or place; older writing has alien from, naming what one is shut out of.

    Similaroutsider, outcast, stranger

    Oppositeinsider

    Note

    The estranged outsider of scripture and sermon. The King James Bible of 1611 speaks of "aliens from the commonwealth of Israel," and Philip Mauro in 1928 pairs "aliens and enemies of God." The exclusion is spiritual, from a covenant or a fellowship.

    Checked 2 Nov 2026 · 5 facts

  2. 8
    verbarchaic
    To make someone feel estranged or no longer connected; to alienate.
  3. 9
    verb
    To transfer the ownership of property or a right to another party.

Practice

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Origin

This word came into Middle English from Old French alien, which came from Latin aliēnus ("belonging to someone else," and later "exotic, foreign"). That in turn came from Latin alius ("other"), and it is related to the English word else.

Checked 31 Oct 2026 · 3 facts

  • Alien entered Middle English from Old French alien, ultimately from Latin aliēnus, meaning belonging to someone else and later exotic or foreign. en.wiktionary.org
  • Latin aliēnus derives from alius, meaning other. en.wiktionary.org
  • Alien is etymologically related to English else. en.wiktionary.org