annunciator

Plural: annunciators

Noun

• an indicator that announces which electrical circuit has been active (as on a telephone switchboard)
• Anything that announces something.
• Anything that announces something.
• An officer in the church of Constantinople, whose business it was to inform the people of the festivals to be celebrated.
• A signalling device that shows which of several electrical circuits is active, especially such a device in a telephone switchboard.
• A buzzer in a signal box that sounds when a train activates a treadle positioned on the track, and thus provides a warning or announcement of a nearby train.