It used to only be used to refer to people who got exiled from their home country, don't really know when the use shifted to a wider meaning, it had to be sometime around or after WW2 as I do remember reading the expat community still referring primarily to exiles and foreign writers and journalists in the 1930s. I will say that immigrant technically means permanent moving, but there's absolutely anglocentrism and classism on who gets called an expat and who gets called a migrant worker and expat communities often came during decolonization to be sort of colonial holdovers.
It used to only be used to refer to people who got exiled from their home country, don't really know when the use shifted to a wider meaning, it had to be sometime around or after WW2 as I do remember reading the expat community still referring primarily to exiles and foreign writers and journalists in the 1930s. I will say that immigrant technically means permanent moving, but there's absolutely anglocentrism and classism on who gets called an expat and who gets called a migrant worker and expat communities often came during decolonization to be sort of colonial holdovers.