0 coming from a different country, race, or group: --
an alien spacecraft
When I first went to New York, it all felt very alien to me.
an alien culture
1 someone who lives in a country of which they are not a legal citizen: --
2 a person who lives in a country but is not a citizen (= member of a country with specific rights) --
3 coming from a different country, race, or group; foreign: --
alien customs
4 a person who lives in a foreign country of which they are not a citizen: --
illegal aliens