reserved seat
unreserved seat; non-reserved seat
指定席は早めに取った方がいい。
It's better to get reserved seats early.
人気のコンサートは指定席がすぐに売り切れる。
Reserved seats for popular concerts sell out quickly.
彼はいつも窓際の指定席に座る。
He always sits in his usual reserved seat by the window.