Network File

File System - File Descriptor or Handle (Open File)

A file descriptor (Unix, Linux) or a file handle (Windows) is the connection id (generally to a file) from the Operating system in order to perform IO operations (Input/Ouput of Bytes). For Wikipedia "...

TCP - Connection

in TCP A TCP server may serve several clients concurrently with the same local socket address (ie local IP address and port number) by creating a child process for each client for each connection. A "...