noun
A room in a house or hotel where meals are eaten. Often used in Western-style contexts; the Japanese-style equivalent is 食堂 (しょくどう).
新しい家には広いダイニングルームがある。
The new house has a spacious dining room.
ホテルのダイニングルームで朝食をとった。
We had breakfast in the hotel's dining room.
Variant with interpunct; less common but sometimes seen in signage or menus.
食堂 is a more general term for a dining room or cafeteria, often with a Japanese or institutional feel, while ダイニングルーム specifically refers to a Western-style dining room in a home or hotel.
Loanword from English 'dining room', adopted into Japanese with katakana spelling.