middle school section; junior high school division
Refers specifically to the middle school grades within a combined school that also has elementary and/or high school sections. Often used in private school contexts.
See also: 高等部
This school has an elementary division, a middle school division, and a high school division.
He is a student in the middle school division.
高等部 is the high school division of the same type of combined school.
Compound of 中等 (middle grade) and 部 (section, division).