A socket is a communication mechanism that allows client/server systems to be developed either locally, on a single machine, or across networks. Linux functions such as printing, connecting to databases, and
serving web pages as well as network utilities such as rlogin for remote login and ftp for file transfer usually use sockets to communicate.
Sockets are created and used differently from pipes because they make a clear distinction between client and server. The socket mechanism can implement multiple clients attached to a single server.

In simple words we can say, Sockets are basically an extension of pipe.
First, a server application creates a socket, which like a file descriptor is a resource assigned to the server
process and that process alone. The server creates it using the system call socket, and it can’t be shared
with other processes.
The server process gives the socket a name. Local sockets are given a filename in the Linux file system, often to be found in /tmp or /usr/tmp. For network sockets, the filename will be a service identifier (port number/access point) relevant to the particular network to which the clients can connect. This identifier allows Linux to route incoming connections specifying a particular port number to the correct server process.A socket is named using the system call bind. The server process then waits for a client to connect to the named socket. The system call, listen, creates a queue for incoming connections. The server can accept them using the system call accept. When the server calls accept, a new socket is created that is distinct from the named socket. This new socket is used solely for communication with this particular client. The named socket remains for further connections from other clients. If the server is written appropriately, it can take advantage of multiple connections. A web server will do this so that it can serve pages to many clients at once. For a simple server, further clients wait on the listen queue until the server is ready again. The client side of a socket-based system is more straight forward. The client creates an unnamed socket by calling socket. It then calls connect to establish a connection with the server by using the server’s named socket as an address. Once established, sockets can be used like low-level file descriptors, providing two-way data communications.