1859, from Fr.
dolmin applied 1796 by Fr. archaeologist Latour d'Auvergne, perhaps from Cornish
tolmen "enormous stone slab set up on supporting points," such that a man may walk under it, lit. "hole of stone," from Celt.
men "stone." Some suggest the first element may be Bret.
taol "table," a loan-word from L.
tabula "board, plank," but the Bret. form of this compound would be
taolvean. "There is reason to think that this [
tolmen] is the word inexactly reproduced by Latour d'Auvergne as
dolmin, and misapplied by him and succeeding Fr. archaeologists to the
cromlech" [OED]. See
cromlech, which is properly an upright flat stone, often arranged as one of a circle.