Windows Sockets

Windows Sockets is the mechanism for communication between applications running on
the same computer or those running on different computers which are connected to a
LAN or WAN. Windows Sockets defines a set of standard API’s that an application uses
to communicate with one or more other applications, usually across a network. Windows
Sockets supports initiating an outbound connection, accepting inbound connections,
sending and receiving data on those connections, and terminating a session.


Windows socket is a port of the Berkeley Sockets API that existed on Unix, with
extensions for integration into the Win16 and Win32 application environments. Windows
Sockets also includes support for other transports such as IPX/SPX and NetBEUI.
Windows Sockets supports point-to-point connection-oriented communications and
point-to-point or multipoint connectionless communications when using TCP/IP.
Windows Socket communication channels are represented by data structures called
sockets. A socket is identified by an address and a port,
for example;
131.107.2.200:80

A more detailed explanation is here...
Image Credits: burks.bton.ac.uk