In recent years, with the popularity of science fiction books and films, this word has been used more and more in the context of “extra-terrestrial, being from another planet”. In British English, it is used only extremely rarely to mean ‘foreigner’, and there are references to this in popular culture at the expense of US English, where it continues to have this meaning; such as in the song by Sting Englishman in New York, where he sings “I’m an alien, I’m an Englishman in New York” precisely because it sounds strange to the British listener.
It is interesting that it should sound strange, as that is precisely what the word once meant. You can see it in the meaning of foreigner – a person from a strange country. And what is an extra-terrestrial if not a being from a strange planet?
It came into English during the fourteenth century. We can see a few examples of it where it is used in different contexts, with differing meanings. Our first example comes from Guy de Chauliac’s medical text dating from 1425 Grande Chirurgie.
If any man..falle fro hyȝnez &..seiþ aliene or straunge þinges , it is to suppose þat þe brayne..is hurt.
If anyone falls from a height and sees alien (peculiar) or strange things, it is to suppose that the brain is hurt.
In this example, the meaning of ‘alien’ is ‘odd, strange, peculiar’. Nothing to do with anything extraterrestrial or even from other countries. But if you think of it in terms of ‘foreign to me’, you can see how the sense developed.
Another example, also from the same time period, is in the Wycliffite Bible.
Bifore me þou schalt not haue noon alien goddis.
Before me thou shalt not have any alien (foreign) gods
In this context, the word is used to mean ‘from another place, foreign’. So you can see that during the fifteenth century, it was used in several different ways.
But where did it come from? Well, it was borrowed into Middle English from Old French, where it also meant strange or foreign. But Old French is not the start of the tale: it borrowed the word from Latin alienus. In Latin it meant ‘foreign, strange’ but also ‘of someone else, belonging to someone else’ – and it is not a large stretch to see that ‘of someone else’ can become ‘of another country’. It was formed from the Latin adverb alius, which meant ‘another, other, different’.
From Latin we go back to Proto-Indo-European *al- which would have meant ‘other’ or ‘beyond’ (elsewhere). We can also see words formed from this root in Greek, such as άλλος [allos], meaning ‘other, another’ or the adverb αλλιώς [allios], meaning ‘otherwise’.
Glossologics 