A small text file stored on a client machine that may later be retrieved by a web server from the machine. Cookies allow web servers to keep track of the end user’s browser activities, and connect individual web requests into a session. Cookies can also be used to prevent users from having to be authorized for every password protected page they access during a session by recording that they have successfully supplied their username and password already. Cookies may be referred to as "first-party" (if they are placed by the website that is visited) or "third-party" (if they are placed by a party other than the visited website). Additionally, they may be referred to as "session cookies" if they are deleted when a session ends, or "persistent cookies" if they remain longer. Notably, the General Data Protection Regulation lists this latter category, so-called "cookie identifiers," as an example of personal information. The use of cookies is regulated both by the GDPR and the ePrivacy Directive (see Cookie Directive).

Associated term(s): First-Party Cookie, Persistent Cookie, Third-Party Cookie, Tracking Cookie, Web Cookie