A dolmen (/ˈdɒlmɛn/) is a type of single-chamber megalithic tomb, usually consisting of two or more vertical megaliths supporting a large flat horizontal capstone ("table"), although there are also more complex variants. Most date from the early Neolithic (4000–3000 BC). Dolmens were typically covered with earth or smaller stones to form a tumulus. In many instances, that covering has weathered away, leaving only the stone "skeleton" of the burial mound intact.
It remains unclear when, why, and by whom the earliest dolmens were made. The oldest known dolmens are in Western Europe, where they were set in place around 7,000 years ago. Archaeologists still do not know who erected these dolmens, which makes it difficult to know why they did it. They are generally all regarded as tombs or burial chambers, despite the absence of clear evidence for this. Human remains, sometimes accompanied by artefacts, have been found in or close to the dolmens which could be scientifically dated using radiocarbon dating. However, it has been impossible to prove that these remains date from the time when the stones were originally set in place.
The word dolmen has a confused history. The word entered archaeology when Théophile Corret de la Tour d'Auvergne used it to describe megalithic tombs in his Origines gauloises (1796) using the spelling dolmin (the current spelling was introduced about a decade later and had become standard in French by about 1885). The Oxford English Dictionary does not mention "dolmin" in English and gives its first citation for "dolmen" from a book on Brittany in 1859, describing the word as "The French term, used by some English authors, for a ...". The name was supposedly derived from a Breton language term meaning "stone table" but doubt has been cast on this, and the OED describes its origin as "Modern French". A book on Cornish antiquities from 1754 said that the current term in the Cornish language for a cromlech was tolmen ("hole of stone") and the OED says that "There is reason to think that this was the term inexactly reproduced by Latour d'Auvergne [sic] as dolmen, and misapplied by him and succeeding French archaeologists to the cromlech". Nonetheless it has now replaced cromlech as the usual English term in archaeology, when the more technical and descriptive alternatives are not used.