[KyleGoetz]

chryuop, if you use a word in Italian and it's not a rare occurence in the language, it's Italian.

Tangram, I consider "a priori" an English phrase because I use it on a regular basis as a native speaker.I consider Deus ex machina and English phrase as well. "Ergo" I'm not so sure about because I never hear anyone using it unless they're trying to be pretentious by using Latin words.

And so what if an English student wouldn't use the word? They wouldn't learn the word "aglet" either, but that's undeniably an English word. What is your criteria for "word in XXX language"? What makes "fjord" an English word but "a priori" not English?

I mean, would you consider コンピューター not Japanese? Would you consider しよう not Japanese because it's a Japanese attempt at pronouncing the Chinese 使 and 用?