A private tutoring school (juku) that offers lessons outside regular school hours, often for exam preparation or extra academic support.
中学受験のために週に三回塾に通っている。
He attends cram school three times a week to prepare for junior high entrance exams.
塾の先生は分かりやすく説明してくれた。
The tutor at the juku explained things clearly.
夏休みに塾で夏期講習を受ける予定だ。
I plan to take summer intensive classes at a cram school during summer vacation.