In ordinary use chiefly applied to those who speak a foreign language as their native tongue; thus in England the term is not commonly understood to include Americans. [OED]
In American English from 1620s through mid-19c., however, it was used of a person from a different colony or state. Earlier as a noun in English was simple foreign (early 14c.), probably from Old French, which used the adjective as a noun meaning "foreigner;" also "outskirts; the outside world; latrine, privy." Spelling furriner, representing pronunciation, is from 1832, originally in Irish dialect pieces but by 1840s picked up by American dialect writers (Thomas Chandler Haliburton).
term for a European or Anglo-American, 1847, from American Spanish gringo "foreigner," from Spanish gringo "foreign speech, unintelligible talk, gibberish," perhaps ultimately from griego "Greek." The "Diccionario Castellano" (1787) says gringo was used in Malaga for "anyone who spoke Spanish badly," and in Madrid for "the Irish." Hence the American Spanish verb engringarse "to act like a foreigner."
before vowels, xen-, word-forming element meaning "strange, foreign; stranger, foreigner," from Greek xenos "a guest, stranger, foreigner, refugee, guest-friend, one entitled to hospitality," cognate with Latin hostis, from PIE root *ghos-ti- "stranger, guest, host." "The term was politely used of any one whose name was unknown" [Liddell & Scott].
1520s, of a people of what is now souther and southeastern Belgium, also of their language, from French Wallon, literally "foreigner," of Germanic origin (compare Old High German walh "foreigner"). The people are of Gaulish origin and speak a French dialect. The name is a form of the common appellation of Germanic peoples to Romanic-speaking neighbors. See Vlach, also Welsh. As a noun from 1560s; as a language name from 1640s.
late 14c., "unknown person, foreigner," from strange + -er (1) or else from Old French estrangier "foreigner" (Modern French étranger), from estrange. Latin used the adjective extraneus as a noun to mean "stranger." The English noun never picked up the secondary sense of the adjective. As a form of address to an unknown person, it is recorded from 1817, American English rural colloquial. Meaning "one who has stopped visiting" is recorded from 1520s.
"foreigner, citizen of a foreign land," early 14c., from alien (adj.) or from noun use of the adjective in French and Latin. In the science fiction sense "being from another planet," from 1953.
also Walach, one of a Rumanian people, 1786, from German Wallache, from Old Church Slavonic Vlachu, from Old High German wahl "foreigner, one speaking a foreign language" (see Vlach). Related: Wallachia; Wallachian.
"member of a Latin-speaking race of the Balkans, a Walachian or Rumanian," 1841, from Bulgarian vlakh or Serbian vlah, from Old Church Slavonic vlakhu, a Slavic adoptation of Germanic *walh (source of Old English wealh) "foreigner," especially applied to Celts and Latins (see Welsh).
c. 1300, "strange, foreign," from Old French alien "strange, foreign;" as a noun, "an alien, stranger, foreigner," from Latin alienus "of or belonging to another, not one's own, foreign, strange," also, as a noun, "a stranger, foreigner," adjective from alius (adv.) "another, other, different" (from PIE root *al- (1) "beyond").
The meaning "residing in a country not of one's birth" is from mid-15c. The sense of "wholly different in nature" is from 1670s. The meaning "not of this Earth" is recorded by 1920. An alien priory (mid 15c.) is one owing obedience to a religious jurisdiction in a foreign country.
"one versed in the Chinese language or Chinese culture and history," 1814; see Sino- + -logy + -ist. Sinology as "branch of knowledge that deals with the Chinese language and related subjects" is by 1834. Related: Sinological. Sinologue (1853) was "a foreigner who is versed in the Chinese language or Chinese culture and history."