noun
school building; schoolhouse
Refers to the physical building or structure of a school, not the institution itself.
新しい校舎はとてもきれいです。
The new school building is very beautiful.
校舎の裏に小さな庭があります。
There is a small garden behind the school building.
学校 refers to the school as an institution or concept, while 校舎 specifically means the physical building.
Compound of 校 (school) and 舎 (building, house).