A seat or section where smoking is prohibited (e.g., in restaurants, trains).
レストランで禁煙席をお願いします。
I'd like a non-smoking table at the restaurant, please.
この電車は禁煙席が多くて、子ども連れでも安心だ。
This train has many non-smoking seats, so it's safe for people with children.
映画館は全席禁煙席になっている。
The cinema has become completely non-smoking.