noun
school lunch duty; lunch monitor
Refers to the role or the students responsible for serving and cleaning up school lunches, typically on a rotating basis in Japanese elementary and junior high schools.
See also: 給食係 (きゅうしょくがかり)
今週は私たちの班が給食当番です。
Our group is on school lunch duty this week.
The lunch monitor's job is to serve the food and clean up afterwards.