A small data file stored on your computer by a website, in theory to allow it to ‘remember’ your preferences, but in practise mostly used to track which adverts you have seen. You can set most browsers to reject all cookies, or to ask your permission before storing them, but this will generate multiple error messages on a lot of websites and is generally more hassle than it’s worth - they are pretty harmless. UK websites are required to display a warning message about them because no-one could make Prime Minister David Cameron understand what they do.
— Computer Sciencea piece of information sent by a Web- Server- to a Web- Browser- that the Browser software is expected to save and to send back to the Server whenever the browser makes additional requests from the Server.
— Computer Science