school nurse's office; health room; infirmary
Typically refers to the room in a school where students go when they feel unwell or get minor injuries; also used for similar facilities in some workplaces.
頭が痛かったので、保健室に行った。
I had a headache, so I went to the school nurse's office.
保健室の先生にけがの手当てをしてもらった。
The school nurse treated my injury.
保健室 is a small first-aid room found in a school, while 保健所 is a full government public health facility serving a whole community.
going to the school infirmary instead of class
Compound of 保健 (health preservation) and 室 (room).