1 [C] (plural standbys) a thing or person that can be used if needed, for example if sb/sth is not available or in an emergency 备用的事物；后备人员: We always keep candles as a standby in case there is a power cut. 我们总是留着蜡烛备用，以防停电。

2 [U] the state of being ready to do sth immediately if needed or if a ticket becomes available 准备就绪；随时候命: Ambulances were on standby along the route of the marathon. 马拉松赛跑时，沿途都有待命的救护车。We were put on standby for the flight to Rome. 我们在等待候补机位飞往罗马。 standby adj (only before a noun 只用于名词前) a standby ticket/passenger 候补机票；候补旅客