What is a socket in network programming?

A socket is an endpoint for communication between two machines, identified by IP address and port number. Socket API enables applications to send/receive data over the network. Types: Stream sockets (TCP, connection-oriented), Datagram sockets (UDP, connectionless). Operations: create socket, bind to port, listen/connect, accept connections, send/receive data, close. Server creates listening socket, accepts client connections, creating new socket per connection.