seal sth off to prevent people from entering an area or building, often because it is dangerous 阻止人们进入一个区域或建筑物，通常是因为那里很危险;封锁，隔离 Two more bombs have been discovered since the police sealed off the area. 警察将这个地区封锁后，又发现了两枚炸弹。 Windows are usually sealed off. 窗户通常是封闭的。