1A seat — a designated place to sit, typically used for theaters, trains, planes, or venues. A somewhat more formal word than plain "席".
座席は予約時に指定できます。
Seats can be assigned at the time of reservation.
満席で座席が一つも残っていなかった。
It was fully booked; there wasn't a single seat left.
優先座席には妊婦さんや高齢者が座っていた。
Pregnant women and elderly people were sitting in the priority seats.
会場の座席表を確認してください。
Please check the seating chart for the venue.