noun
supplementary Japanese school (outside Japan); weekend Japanese school
A school established abroad to provide Japanese-language education and other subjects to children of Japanese residents, typically operating on weekends.
彼女は毎週土曜日に補習授業校に通っている。
She attends a supplementary Japanese school every Saturday.
補習授業校では国語と算数を教えている。
At the supplementary Japanese school, they teach Japanese language and arithmetic.
日本人学校 is a full-time Japanese school abroad following the Japanese curriculum, while 補習授業校 is a part-time supplementary school, often held on weekends.
Compound of 補習 (supplementary learning), 授業 (class/lesson), and 校 (school). The term describes a specific type of educational institution for Japanese children living overseas.