A cookie is a small file, typically of letters and numbers, that is put on your device. Cookies allow a website to recognise a user's device.
This site uses session and persistent first party cookies.

Session cookies expire after a browser session, so they are not stored longer term. For this reason session cookies may sometimes be considered less privacy intrusive than persistent cookies.

Persistent cookies are stored on a user's device in between browser sessions which allows the preferences or actions of the user across a site to be remembered.