1A plate that is used to give a signal or that serves as a signal, especially to road or rail traffic.
2(In some types of television camera tube) a plate electrode whose capacitance relative to an adjacent photoelectric surface is used to provide the picture signal.
Origin
Mid 19th century.
Definition of signal plate in US English:
signal plate
noun
1A plate that is used to give a signal or that serves as a signal, especially to road or rail traffic.
2(In some types of television camera tube) a plate electrode whose capacitance relative to an adjacent photoelectric surface is used to provide the picture signal.