a room for one person; a private room used by an individual (one's own room)
一人暮らしだから、広めの個室を探している。
Because I live alone, I'm looking for a fairly spacious private room.
大学の寮で個室を選べるのはありがたい。
It's nice that you can choose a private room in the university dorm.
入院中は個室だと静かで休みやすい。
Being in a private room while hospitalized is quiet and easier to rest in.
a private room in a restaurant or similar establishment (private dining room)
接待だから、予約で個室をお願いした。
Since it's for entertaining a client, I reserved a private room.
忘年会は個室でやるほうが気兼ねがなくていい。
It's nicer to hold the year-end party in a private room since people feel less restrained.
コロナ対策で個室を利用する人が増えた。
More people have been using private rooms as a COVID-19 measure.
a toilet stall; an individual cubicle in a restroom
トイレの個室は今全部埋まっています。
All the toilet stalls are occupied right now.
授業中にトイレの個室を使ってもいいか先生に聞いた。
I asked the teacher if I could use a restroom stall during class.