Definition
A chambered cairn is a burial monument, usually constructed during the Neolithic, consisting of a sizeable (usually stone) chamber around and over which a cairn of stones was constructed. Some chambered cairns are also passage-graves. They are found throughout Britain and Ireland, with the largest number in Scotland.
Typically, the chamber is larger than a cist, and will contain a larger number of interments, which are either excarnated bones or inhumations (cremations). Most were situated near a settlement, and served as that community's "graveyard".
Chambered cairn en.wikipedia.org