school day

(noun) any day on which school is in session. Synonyms: school day. Example: "Go to bed early because tomorrow is a school day."

(noun) the period of instruction in a school; the time period when school is in session. Synonyms: school, schooltime, school day. Examples: "Stay after school." "He didn't miss a single day of school." "When the school day was done we would walk home together."