an opening or hollow that forms a holder for something
Socket
white, glowing, or luminous with intense heat
Incandescent
an electromagnetic device for remote or automatic control that is actuated by variation in conditions of an electric circuit and that operates in turn other devices (such as switches) in the same or a different circuit
Relay
an electric lamp in which the discharge takes place through mercury vapor
Mercury - vapor lamp
something that is installed for use
Installation
a backup pathway that provides an alternating route for the current to flow back to the ground if there is a fault in the wiring system
Grounding
a complete lighting unit
Luminaire