This is the 8001st most frequent Korean word.
american
The Korean word "아메리칸" (American) refers to something or someone from America, typically the United States.
In this sentence, the word '미국' modifies '친구' to specify that the friend is American.
이 음식은 미국 친구가 추천해 준 거예요.
This food was recommended by my American friend.
Here, '미국' acts as an adjective describing the type of university, specifically American.
저는 미국 대학교에서 유학했어요.
I studied abroad at an American university.
In this context, '미국' directly refers to the country America, used as a proper noun.