Cromlech
2 of the 7 encyclopedias on this shelf carry an entry for Cromlech. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
krom'lek, an ancient Celtic place of burial. It consists essentially of three or more upright stones supporting an uneven slab, beneath which sepulchral remains are found. Very frequently the cromlech shelters a burial urn or chamber, lined with stones and containing a skeleton, with weapons, pottery, and other indications that the dead were persons of rank. These sepulchres are commonest in the territory last occupied by the Celts, as Ireland, Scotland, Wales, Cornwall, Devonshire, and Brittany; but they are found throughout England and many localities of the continent. Sometimes a slab is no larger than two persons may lift. Many are very heavy, however. That of a celebrated cromlech in Cornwall is calculated to weigh twenty tons; the capstone of one in Wales is 12 feet long, 10 feet wide, and 4 feet thick; one near Dublin, resting on 6 blocks, is 23 feet long, 17 feet wide, and 6 feet thick; the Witches' Stone in the vicinity of Edinburgh is about 10 feet wide and 12 feet in length. See Catacombs ; Mummy
Collier's New Encyclopedia (1921)
an erection consisting of two or more stones standing like pillars, with a large flat, or rather a slightly inclined one, placed upon the top, so as to make the whole present a rude resemblance to a table. Two fine cromlechs exist at Plas Newydd in Anglesea; others, less notable, are scattered through Wales; they exist also in Scotland, Jersey, Brittany, and throughout ghout the Celtic area. Formerly they were generally held to be old altars for sacrifices. Modern opinion holds them to have been sepulchers. A cromlech is called also a dolmen. Somewhat similar erections are seen in various parts of Europe, in Arabia, in India, and North and South America.