Winsock

In computing, the Windows Sockets API (WSA), later shortened to Winsock, is an application programming interface (API) that defines how Windows network application software should access network services, especially TCP/IP. It defines a standard interface between a Windows TCP/IP client application (such as an FTP client or a web browser) and the underlying TCP/IP protocol stack. The nomenclature is based on the Berkeley sockets API used in BSD for communications between programs.