noun
Common loanword used in compounds like ルームサービス (room service) or ルームメイト (roommate), and sometimes as a standalone noun for a room in a building or facility.
ホテルのルームサービスを頼んだ。
I ordered room service at the hotel.
このルームは広くて快適だ。
This room is spacious and comfortable.
部屋 is the native Japanese word for 'room' and is more common in everyday conversation. ルーム is a loanword often used in compound terms or to give a modern, Western feel.
Borrowed from English 'room'.