day boy 
noun British
A boy who lives at home but attends a school where other pupils board.I shared my large room with Andy, a day boy, and so had the place to myself at night....
- He himself had attended the school and recalled that there were 82 pupils there at the time, all boarders except one day boy, and one lay teacher.
- In those days it was still a boarding school, though half were day boys from local neighbourhoods like myself.