lamp socket
Device composed of a socket, its protective components and a switch.
parts of a lamp socket 
outer shell 
Decorative component covering the socket and the insulating sleeve.
insulating sleeve 
Component protecting the outer shell from the heat.
socket 
Device into which a lamp’s base is inserted in order to connect it to the electric-supply circuit and to keep it in place.
cap 
Component fitting onto the outer shell and covering the upper end of a lamp’s socket.