Refers to a room with a bathtub and/or shower, typically in a home, hotel, or public facility. More specific than トイレ (toilet).
ホテルの浴室はとても広かった。
The hotel bathroom was very spacious.
浴室のカビを掃除する。
I clean the mold in the bathroom.
As soon as he got home from work, he went straight into the bathroom.
After the trip, I felt refreshed after taking a shower in the bathroom.
I always clean the bathroom on weekends.