|welcome||welcome spring||welcome||beautiful day||welcome mouse|
From Middle English welcome, wolcume, wulcume, wilcume, from Old English wilcuma (,,one whose coming is pleasant, a welcome person or thing, a guest"; compare also wilcume (,,welcome!”, interjection), from Proto-Germanic *wiljakwumô (,,a comer, a welcomed guest”), equivalent to will (,,desire”) + come (,,comer, arrival”). Cognate with Scots walcome (,,welcome”), West Frisian wolkom (,,welcome”), Dutch welkom (,,welcome”), German willkommen (,,welcome”), Danish and Norwegian velkommen (,,welcome”), Swedish välkommen (,,welcome”), Icelandic velkomin (,,welcome”), Low Saxon: walkommen.
Similar constructions are common in Romance languages, such as Italian benvenuto, Spanish bienvenido, French bienvenue, Catalan benvingut, Portuguese bem-vindo and Romanian bun venit, each meaning ,,[may you have fared] well [in] coming [here]”. These do not derive from Classic Latin, where a similar construction is not found, and presumably are instead the result of a calque from Germanic to Proto-Romance.
Used with ,,in" when referring to a place, as in ,,I felt welcome in England", and when saying that one would like to welcome someone (before they have arrived or even if they are being prevented from coming), as on banners saying ,,Refugees welcome in London!" (short for ,,Refugees are welcome in London!").
So in a country that is not preventing refugees from coming, both banners saying ,,Refugees, welcome to X!" (the interjection ,,welcome", with a comma) and ,,Refugees welcome in X!" (the adjective ,,welcome", without a comma) are correct but mean different things.
The interjection ,,welcome" is always used with ,,to" or without any preposition (,,welcome home", ,,welcome back"). ,,Welcome to X" is only used when greeting people, never when saying that one would like to invite them or is looking forward to seeing them.
The adjective ,,welcome" is also used with ,,to" before nouns that are not places and before verbs in the expressions ,,be welcome to something" (e.g. the last piece of cake) and ,,be welcome to do something" (e.g. to take as much cake as you want).
When used with reference to a place, ,,welcome" is always followed by ,,to". The signs often seen in many non-English-speaking countries welcoming tourists with ,,in", such as ,,Welcome in Heidelberg!", sound unnatural to English speakers and show interference from other languages, many of which use a cognate of ,,in" in this situation, and especially with a cognate of ,,welcome".
The adjective ,,welcome" is used with both ,,in" and ,,to" but in different contexts.