A private room in a home used for reading, study, or work; a home office or study.
父は毎朝書斎で新聞を読む。
My father reads the newspaper in his study every morning.
書斎に本棚を増やして、作業スペースを広げた。
I added more bookshelves to the study and expanded the workspace.
在宅勤務になって、書斎を仕事用に整えた。
Since I started working from home, I set up the study as a work room.