Small amount of data generated by a website and saved by your web browser. Its purpose is to remember information about you, similar to a preference file created by a software application.
Most common purpose is to store login information for a specific site. Some sites will save both your username and password in a cookie, while others will only save your username. Whenever you check a box that says, “Remember me on this computer,” the website will generate a login cookie once you successfully log in. Each time you revisit the website, you may only need to enter your password or you might not need to log in at all.