Why is the word "expat" a thing?

In theory, An expat is someone sent abroad on short/mid-term mission while working for an employer, while a migrant is someone moving abroad to find a job and sometimes to start a new life.
This means that, if let's say if a Mining company in Ghana sends someone to New-York to be the "US sales director" that person would be an an expat While an American opening an hotel in Ghana would be an immigrant.
But indeed, in many cases : Expat = European/North-American, Immigrant = From somewhere else
- Solid explanation. I'd only add that I see the word in fiction used to describe Europeans and Americans as expats if they've been overseas for years and not even working. Seems to be people who eventually mean to return home.
- This is all ive ever seen in my career which includes lots of overseas work.

Because "immigrant bad" and they don't see themselves as bad.
- They see themselves on an extended holiday of multiple decades.
- Hear me out:
  Maybe everything isn't some conspiracy to hate others.
  
  ah, so you have an alternative explanation?
- To be fair, they are pretty bad, unless you do like America and only allow people with certain skills and intelligence. Allowing refugees from war torn countries is very nice, but ultimately brings that war to the country itself and changes the culture into something very different.
  Source: Sweden.
  
  🤮
  
  Bro skilled people wanting to become US residents or citizens have to wait an absurd amount of time to even have a chance

A quick Google search says that an expat usually only lives in a new place for a limited period of time. An immigrant moves to a new place with intent to settle.
Whether that's how it's used colloquially is another matter...

I've always considered an expat to be different from immigrant in that it's temporary.
I lived abroad from 2009 to 2011, simply because I could, as my employer had to fly me in to work anyway - It didn't matter to me whether my home airport was TRD or PRG. I was chatting with someone local, and when I told them about my situation they're actually the ones who used the word expat. Personally I considered myself a long term tourist.

Because immigrants are brown and poor.

Personally, I define an expat as someone living in another country and not learning the language/customs.
They will never be accepted as a local because of this.

Why Brits and Americans? Every major city has expats.
You go abroad for a job, usually temporarily -> expat
You give up your citizenship to move to another country -> immigrant
- Migrant worker is a term
  
  I've seen that term used for folks who go to a place seeking work in a large industry that will just accept all comers in the right season. An expat is sent on appointment, same company, different country, fixed time duration.
  Perception is absolutely a thing though, I expect expats or similar wouldn't describe themselves as migrant workers.
  
  Migrant worker is the term for expats who aren't white.
- Historically a lot of American and British authors and artists used the term

The etymology might help break down some of the nuance here
According to etymonline the etymology for expatriate (often shortened to expat) is:
"to banish, send out of one's native country," 1768, modeled on French expatrier "banish" (14c.), from ex- "out of" (see ex-) + patrie "native land," from Latin patria "one's native country," from pater (genitive patris) "father" (see father (n.); also compare patriot). Related: Expatriated; expatriating. The noun is by 1818, "one who has been banished;" main modern sense of "one who chooses to live abroad" is by 1902.
Immigrate, is similar, but is more used to describe moving to a place:
"to pass into a place as a new inhabitant or resident," especially "to move to a country where one is not a native, for the purpose of settling permanently there," 1620s, from Latin immigratus, past participle of immigrare "to remove, go into, move in," from assimilated form of in- "into, in, on, upon" (from PIE root *en "in") + migrare "to move" (see migration). Related: Immigrated; immigrating.
The closer synonym to expatriate would probably be emigrate, the opposite of immigrate, to leave a place.
As to why one might use expatriate over emigrate; consider the sentence "I'm an American immigrant". It's kind of unclear if you're trying to say that you are an American that has migrated to another country (as in "I'm an American immigrant living in Brussels"), or someone who has migrated to America (as in "I'm an American immigrant from Slovakia"). Using expatriate removes the ambiguity: "I'm an American expatriate" and makes it clear that the speaker is trying to convey where they are from.
technically, using emigrant here would be more clear, but English is a lawless and lazy language
- Thank you for this; I was thinking expat would be closer to emigrant than immigrant. I associate expat and emigrant with describing where someone is from while immigrant describes where someone has arrived.
  
  To be an immigrant you must first be an emigrant. Emigrants leave their country, immigrants join a country.
- Side note, we should bring back the traditional practice of banishment as a punishment for people who society has agreed are too insufferable to be around.
- Immigrant/emigrant sound too similar to be generally usable. Lawless and lazy probably aren't the culprit here.

Immigrant would be someone coming to your country, emigrant is someone leaving your country. So an expat would be an emigrant if anything. I've always assumed that it's short for ex-patriot, since they left their country to go live in another one.
- Expat is short for expatriate, not ex-patriot. Both expatriate and patriot do come from the same Latin root (patria, fatherland) via French.
  But yes, expatriate means someone who lives outside (ex) of their fatherland (patria) - can be used for both immigrant or emigrant, depending on context.
  
  Thanks!

I always assumed it was simply a matter of perspective. E.g. someone leaving the USA for the UK is an expat to the USA but an immigrant to the UK.

I've always interpreted it as someone who's here only temporarily. They plan to go back eventually and as such stick to expat social groups with similar issues for e. g. temp permits as opposed to permanent permits for immigrants.

cause usually its not permanent, like with immigrants.
- Are you going to tell this to the British expat pensioners in France and Spain? Because they probably never knew that meaning.
  
  You mean Portugal?

Immigration is permanent residence. You can move somewhere not permanently, like on a temporary work visa - that is an expat. US/UK/Canada have a lot of treaty agreements with other countries, so a Canadian citizenship will essentially allow you into many countries more easily than those coming from a third world country. People from third world countries have to go through a more intensive visa process for temporary residence.
Another reason expat applies generally is because generally an expat from the US does not renounce their US citizenship despite the tax implications due to the need/desire to return home. The US is one of the few countries that will tax a US citizen anywhere in the world, which I think leads to the increased use of the word expat.

It's not a British/American thing - any nationality can be referred to as an expat. It's all a matter of what you're trying to emphasize. The term "expat" implies being in a different country and feeling like a foreigner - using the term suggests that there is a degree of culture shock or not feeling like you fully fit in. Foreigners will often look for expat communities for support. That may be why you're noticing it with British and American foreigners - you can be a French expat or a German expat or any other nationality, but if English isn't your first language you're less likely to know the term.
You're also less likely to hear an American or British person refer to people who come to the U.S. or U.K. as "expats" - the term "expat"implies inclusivity with other people who came from the same place, while "immigrant" carries the implication of someone from a different culture that came here. As a native English speaker, I would think it sounds perfectly natural to hear someone say "I'm a Syrian expat", but I would only use the term to describe "the Syrian expat community" (i.e. the Syrians that have come here and are relying on each other for support). If I were describing the same person, I would say "Syrian immigrant" because I'm not the one feeling the culture shock of being in a foreign land. (or I would use the term "refugee" which carries the implication that they're here, but not by choice - they were forced out of their home)
"Immigrant" often also implies some sort of formal legal status, although in a looser sense it just means that you live in that country on a permanent basis. All immigrants are also expats, but not all expats are immigrants.
As others have pointed out here, while neither term is by itself positive or negative, "expat" will almost never be used in a negative sense, but "immigrant" can be used in a derogatory way, although it can also be neutral or positive depending on the speaker and context.

I hear the word expat all over the world, I don't think it's regional.
"immigrant" gives the impression that you are traveling to get to someplace, while expat implies that you are traveling to get away from someplace, as I've heard it used.

I call any non-native citizen (anyone not born in my country) an import.
Like beer.

Colloquially, expat tends to imply self funded, or at least bringing wealth with them in some respect. That's not what the word literally means but it's how I see it used. This is consistent even with foreign professionals coming to work in, say, London. Few people refer to them as immigrants though that's what they are technically. (I've seen people be called an "ex pat from their country" or an "international worker", these both in the city of London referring to office based professionals) The word immigrant seems to be reserved (at least in Britain) as a pejorative because it implies low skill and by further implication, a net cost on public services.

There is another point, at least for Americans. While I know a few people who have emigrated to the US and still maintain ties with their original homeland, I know others who have intentionally given up their privileges back home. While they may still be citizens of their home country, they owe them no obligations.
The US is different, they tax your income no matter where in the world you make it. if you are living in a country with a tax treaty in the US, you can fully deduct all foreign tax payments so you will likely end up owing nothing to the US. But you still have to file. And in return for that you retain the right to vote from the state you last resided in. Furthermore, it is quite hard to give up your US citizenship. It can be very costly, because we will make you pay taxes on assets as if you sold them before they let you leave, including any retirement funds.
Americans living abroad are much more likely to still consider themselves Americans first, because we remind them about it every April 15th.

Everybody is a foreigner in nearly every country on earth.
But, if you want to declare yourself as special, then you start to make up special terms.

Because its a better word

White pipi needs to feel good