As football, baseball, and basketball are all relatively modern things, I might have expected their Korean terms to be transliterations of foreign terms (in the same way that the words 'taxi', 'computer', 'coffee', and so on have come into Korean). I find it intriguing that the common terms for these sports are the Hanja-rooted words '축구','야구', and '농구'.
How did these terms enter the Korean language?