count·down /ˈkaʊntdaʊn/ noun [countableC usually singular]
1.the period of time before something happens, such as a spacecraft being launched, when someone countsbackwards until the event happens 〔发射航天器等事件发生之前的〕倒计时,倒数读秒
2the period of time before an important event, when people become more and more excited about it 倒计时阶段