1. readiness for duty or immediate deployment: "buses were placed on standby for the trip to Washington"
▪ the state of waiting to secure an unreserved place for a journey or performance, allocated on the basis of earliest availability: "passengers were obliged to go on standby"
▪ a person waiting to secure a place on standby.
▪ a person or thing ready to be deployed immediately, especially if needed as backup in an emergency: "a generator was kept as a standby in case of power failure"
▪ an operational mode of an electrical appliance in which the power is switched on but the appliance is not actually functioning.