A cookie is a small text file that a website asks your browser to store on your device. When you open another page on the same site — or return on a later day — the browser sends that file back, so the site can remember something useful. That might be a display preference you set, the language you chose, or simply the fact that you have already dismissed a notice.
Cookies come in two main time horizons. Session cookies last only while your browser is open and are cleared when you close the tab or the window. Persistent cookies stay on the device for a set period, ranging from minutes to several months, and are removed either when that period ends or when you delete them yourself. Neither kind is a program: a cookie cannot run code, and it cannot read other files stored on your device.
Similar technologies do comparable work. Local storage and session storage, for example, let a site keep small pieces of data in your browser without using a cookie. Pixels, tags, and script identifiers function in a related way when they are used for analytics or performance measurement. This cookie policy treats those mechanisms together, because from the visitor's point of view they raise the same question: what is being stored, and why.