if a concert, match, etc. is sold out, there are no more tickets available for it (音乐会、比赛等)票已售完的,满场的,满座的 The Opera House was sold out for the singer’s first appearance in the city. 这位歌手第一次在这个城市露面,歌剧院的票就卖完了。
if a shop is sold out of a product, it has no more of it left to sell (商品)销售一空的