A hollow part in a wall where you can put an electric plug to make something work.
Sockets are useful for making things like lamps and computers work.
Examples:
I plugged my computer into the socket.
The lamp is not working because it's not in the socket.
The socket is where you put the plug to make the TV turn on.
I tried to plug in my phone, but the socket was broken.
There are many sockets in the house to plug things into.
The socket is like a mouth for the electricity to go into.