noun
study room; self-study room
A room where people study on their own, often found in schools, libraries, or private facilities. May be a quiet room for individual work.
図書館の自習室で試験勉強をした。
I studied for the exam in the library's study room.
この塾には静かな自習室がある。
This cram school has a quiet self-study room.
勉強部屋 is a casual term for a study room at home, whereas 自習室 is more formal and typically refers to a designated room in a public or institutional setting.
Compound of 自習 (self-study) and 室 (room). The exact historical derivation is uncertain, but the word follows a common pattern for naming specialized rooms.