IP – Internet Protocol. A set of rules, for routing and addressing data packets so that they can be sent across an Internet network to the correct destination. Data to be transmitted across the Internet is split into small chunks called packets. IP information, such as the destination address, is added to each packet and the data transmitting and receiving devices in the Internet, the routers, use this information to send packets the right way across the Internet. Every Internet device has its own IP address and so the routers can use the packet IP data to ensure packets go to the right Internet end-point device.
Once at the endpoint other protocols direct what happens to them, such as TCP and UDP, for which there are separate entries.