noun
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.
ホテルの客室はとても広かった。
The hotel guest room was very spacious.
船の客室から海が見えます。
You can see the ocean from the ship's cabin.
noun
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.
昔の家には客室があった。
Old houses used to have a drawing room.