taking turns; working in shifts
Refers to a system where people alternate doing something, such as chores, duties, or work shifts.
掃除は回り番でやっています。
We take turns doing the cleaning.
夜勤は回り番で担当する。
We work the night shift in rotation.
Compound of 回り (mawari, 'rotation') and 番 (ban, 'turn' or 'watch'). The exact historical derivation is uncertain, but the meaning is transparent from its components.