cram school; preparatory school
A private school that prepares students for university or high school entrance exams, often attended after regular school hours or during a gap year.
He is attending a cram school to prepare for university entrance exams.
The summer intensive course at the cram school is very demanding.
My brother attends a cram school to prepare for university entrance exams.
I enrolled in a cram school right after graduating high school.
He studies math at a cram school.