단 meaning and usage 단 한번만 제발 넌 영원한 나의 친구 단 하나뿐인 내 친구 니가 돌아오면 잘해주겠단 생각뿐 멋지단 말론 부족한 걸 What does 단 mean, what does it do, and what is its purpose in these sentences? They are all lyrics from different 소녀시대 songs. I cannot find the answer to this anywhere. Also, if you could go further and give more examples and explanations on how 단 is used and when it is used, because it seems like it can be used by itself and as a particle.