共学校
also: きょうがっこう
きょ
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く
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Meanings
1
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.
In this area, most high schools are coeducational.
I'm unsure whether a coeducational school or a boys' school would be better.