This is the 3420th most frequent Korean word.
대표단은
"Delegation" or "The delegation."
Here, '대표단은' (delegation) is used as the subject of the sentence, denoting the group of delegates starting the meeting.
대표단은 회의를 시작했습니다.
The delegation started the meeting.
In this sentence, '대표단은' is again the subject, showing that the delegation is receiving the action of being welcomed.
대표단은 공항에서 환영을 받았습니다.
The delegation was welcomed at the airport.
'대표단은' serves as the subject, indicating that the delegation is actively partaking in the negotiations.