1. Transmission Control Protocol/Internet Protocol. It is the data communication protocol most often used on Linux machines. [Transmission Control Protocol/Internet Protocol] The wide-area-networking protocol that makes the Internet work, and the only one most hackers can speak the name of without laughing or retching. Unlike such allegedly `standard' competitors such as X.25, DECnet, and the ISO 7-layer stack, TCP/IP evolved primarily by actually being used, rather than being handed down from on high by a vendor or a heavily-politicized standards committee. From Linux Guide @FirstLinux

2. Transmission Control Protocol/Internet Protocol. It is the data communication protocol most often used on Unix machines. From NIS HOWTO