A tumulus (plural tumuli) is a mound of earth and stones raised over a grave or graves. Tumuli are also known as barrows, burial mounds or kurgans, and may be found throughout much of the world. A cairn, which is a mound of stones built for various purposes, may also originally have been a tumulus.

Tomb of King Alyattes at Bin Tepe in Lydia, modern Turkey, built circa 560 BCE.[1] It is "one of the largest tumuli ever built",[2] with a diameter of 360 meters and a height of 61 meters.[3]
The Royal mounds of Gamla Uppsala in Sweden from the 5th and 6th centuries; originally the site had 2,000 to 3,000 tumuli, but due to quarrying and agriculture only 250 remain.
La Cambe German war cemetery
One of the Hallstatt culture-era tumuli in the Sulm valley necropolis
Kasta tumulus Amphipolis

Tumuli are often categorised according to their external apparent shape. In this respect, a long barrow is a long tumulus, usually constructed on top of several burials, such as passage graves. A round barrow is a round tumulus, also commonly constructed on top of burials. The internal structure and architecture of both long and round barrows has a broad range; the categorization only refers to the external apparent shape.

The method of inhumation may involve a dolmen, a cist, a mortuary enclosure, a mortuary house, or a chamber tomb. Examples of barrows include Duggleby Howe and Maeshowe.

The word tumulus is Latin for 'mound' or 'small hill', which is derived from the Proto-Indo-European root *teuh2- with extended zero grade *tum-, 'to bulge, swell' also found in tomb, tumor, tumescent, thumb, thigh, and thousand.[4]