When browsing the internet, all that runs through a network are called data, these are broken up into small pieces called packets. Packets are a small segment of a larger data sent over a network. They are sent from your computer to the server hosting the website you're visiting, such as when downloading a file, streaming a video or audio. These packets are then recombined by the computer or device that receives them. Packets are sent back and forth between your computer and the server.