noun
home room; homeroom
Refers to the classroom where a class gathers for administrative matters, announcements, and homeroom period; common in Japanese school settings.
朝の会は主教室で行われます。
The morning meeting is held in the home room.
生徒たちは主教室に戻って連絡を聞いた。
The students returned to the home room to hear the announcements.
ホームルーム is a common loanword for the homeroom period or the classroom itself; 主教室 is a more formal, kanji-based term.
Compound of 主 (しゅ, 'main') and 教室 (きょうしつ, 'classroom'). The exact historical derivation is uncertain, but the term is conventionally used in Japanese school administration.