(1) A communications handle used by TCP/IP.
(2) An identifier that an application uses to uniquely identify an end point of communication. The user associates a protocol address with the socket by associating a socket address with the socket.
(3) A means for directing data to an application in a TCP/IP network using a unique identifier that is a combination of an IP address and a port number.
(4) In the Network Computing System (NCS), a port on a specific host; a communications end point that is accessible through a protocol family's addressing mechanism. A socket is identified by a socket address.
(5) A callable TCP/IP programming interface that TCP/IP network applications use to communicate with remote TCP/IP partners.