/ Dictionary / Index A alien: Meaning and Definition of Find definitions for: al•ien Pronunciation: (āl'yun, ā'lē-un), [key] — n. a resident born in or belonging to another country who has not acquired citizenship by naturalization (distinguished from citizen). a foreigner. a person who has been estranged or excluded. a creature from outer space; extraterrestrial. —adj. residing under a government or in a country other than that of one's birth without having or obtaining the status of citizenship there. belonging or relating to aliens: alien property. unlike one's own; strange; not belonging to one: alien speech. adverse; hostile; opposed (usually fol. by to or from): ideas alien to modern thinking. extraterrestrial. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: alien (Thesaurus) alidade alienable Related Content Daily Word Quiz: profiterole Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language