Cookies - first party and third party
From DigitalJargonBuster
The difference between First-Party and Third-Party Cookies
First party cookies First-party cookies either originate on or are sent by the website (the domain name) of the service currently being used. First-party cookies are commonly used to store information such as user preferences.
Third-party cookies Third-party cookies come from other websites or web services that may be connected to the site you are currently viewing. Third-party cookies are frequently used to track webpage use for advertising or other marketing purposes. Advertising content served into a webpage from somewhere outside that website (such as ‘sponsored links’ columns or banner advertising networks) usually use third-party cookies. Third-party cookies can be either persistent or session cookies.
Fourth-party cookies These are possible when a third party ad server delivers advertising using another party. A common situation is when a third party server is delivering advertising using formats such as Rich Media which are often streamed from another organisation. Cookies associated with the other organisation would be 'Fourth Party' cookies.