Refers to a room for guests in a hotel, inn, or a cabin on a ship or plane. The specific context (hotel, boat, plane) is usually clear from the situation.
The hotel guest room was very spacious.
You can see the ocean from the ship's cabin.
A somewhat formal or old-fashioned term for a room used to receive guests in a private home. In modern Japanese, 応接間 or リビング are more common for this meaning.
Old houses used to have a drawing room.
I reserved three guest rooms at the hotel.
You can check into your room at 3 p.m.
I relaxed in the cabin during the long flight.