For code which uses the Berkley Sockets API (specified by POSIX, and available on Windows too) to communicate with other processes using a network protocol.

A socket, in network computing, is an endpoint of a bidirectional inter-process communication flow across a computer network, such as the Internet.

The Sockets API supports a wide range of protocols (e.g. Unix-domain sockets, TCP/IP, XNS, NetBIOS, ATM, CAN and more). This tag is appropriate for all uses of sockets, regardless of protocol.

An Internet (TCP/IP) socket address is the combination of an IP address (the location of the computer) and a port (which is mapped to the application program process) into a single identity, much like one end of a telephone connection is the combination of a phone number and a particular extension.