We say "U.S. citizen", but why can't we say "China citizen"? Or can we?

Question

Is the word "U.S." an adjective or a noun modifier in this case? It seems to me that it is an adjective that goes before citizen, because we say "Russian citizen", "Chinese citizen", etc. But if it's a noun modifier, then why can't "China" be a noun modifier, too? Although "China citizen" sounds wrong to me, "(People's) Republic of China citizen" doesn't sound as bad. I know I could always write "citizen of China" and in general, "citizen of [country]", but I'm just curious to know.

Answer 1

I'm wondering if the answer may be that U.S. is short for United States, thus United States Citizen sounds familiar to our ears. This is one of the many reasons it is so hard for English language learners to really comprehend the English language. There does not seem to be a fast rule to this situation. We change Ireland to Irish, Germany to German. The newer thought is to say Citizen of China, Citizen of [country]. By saying Citizen first it is not placing a label on the person, but describes their country of origin.

This is also a trend for changing wording describing people. "She has diabetes", as opposed to the formerly common phrase, "She is diabetic". Another example, "He's disabled or handicapped." Or "He's a handicap." We now say, "He has a disability."