also: きょうがっこう
coeducational school; mixed-sex school
Refers to a school where both male and female students are enrolled, as opposed to single-sex schools. Commonly used in educational contexts.
この地域では、ほとんどの高校が共学校です。
In this area, most high schools are coeducational.
I'm unsure whether a coeducational school or a boys' school would be better.