What is Cookie (Data Packet)?

A cookie, sometimes called an internet cookie or HTTP cookie, is a packet of data that a computer receives (and sends back when needed) from a website while a user is browsing the internet. Cookies have various purposes including tracking and storing browsing history, keeping track of online purchases, and for user authentication of login credentials, among other tasks. Cookies are very important in facilitating the proper functionality of the internet as user and networking architecture would not functionally operate without them.