being on duty; person on duty; one's turn to perform an assigned task.
今週は掃除当番だから教室をきれいにしよう。
We're on cleaning duty this week, so let's tidy the classroom.
当番表を見て自分の担当日を確認してください。
Check the duty roster to confirm your assigned day.
当番の人がいない日は交代で対応する。
If the person on duty is absent, others take turns to cover.