call waiting
noun
mass noun
- a service whereby someone making a telephone call is notified of an incoming call on the line that they are already using, typically one that allows the first call to be placed on hold while the second is answered呼入等待（服务）（正在打电话的人被告知有电话打入的服务, 该项服务通常允许通话人让第一个电话待机而接第二个电话）。