- adjective different or not fitting the usual system
- adjective not compatible with the particular system
- noun a person who is not a citizen of the United Kingdom, nor of a Commonwealth country nor of the Irish Republic
- noun a life-form from another planet
- adjective from a different country or culture
- noun a person who is not a citizen of the UK, not a citizen of a Commonwealth country and not a citizen of the republic of Ireland
Origin & History of “alien”
The essential notion contained in alien is of ‘otherness’. Its ultimate source is Latin alius ‘other’ (which is related to English else). From this was formed a Latin adjective aliēnus ‘belonging to another person or place’, which passed into English via Old French alien. In middle English an alternative version alient arose (in the same way as ancient, pageant, and tyrant came from earlier ancien, pagin, and tyran), but this died out during the 17th century. The verb alienate ‘estrange’ or ‘transfer to another’s ownership’ entered the language in the mid 16th century, eventually replacing an earlier verb alien (source of alienable and inalienable).