A day school—as opposed to a boarding school—is an institution where children (or high school age adolescents) are given educational instruction during the day, after which the students return to their homes. The term can also be used to emphasize the length of full-day programs as opposed to after-school programs, as in Jewish day school.
The term day school is also increasingly used for a one-off series of lectures or classes, taking place on a single day, usually on a particular topic and usually directed at adult learners with little time to spare.
References
Day school Wikipedia(Text) CC BY-SA