girls' school
Refers to a school for girls, especially in historical contexts before coeducation became widespread. In modern usage, it may still be used for traditional all-girls institutions.
祖母は女学校で裁縫を習った。
My grandmother learned sewing at a girls' school.
A historic girls' school remains in this area.
Before the war, my grandmother attended a girls' school in Tokyo.
After graduating from her local girls' school, she became a teacher.