day duty; day shift; class duty
Refers to a person assigned to be on duty during the day, especially in schools (a student who helps the teacher) or workplaces. Often used with 〜をする or 〜になる.
I'm on day duty today.
The student on class duty erased the blackboard.
日直 refers to day duty (often in schools or offices during regular hours), while 当直 usually implies overnight or off-hours standby duty despite the shared 直 kanji.
Compound of 日 (day) and 直 (duty, shift). The reading にっちょく is a regular sound change from にち + ちょく.