Noun
A monument of rough stones composed of one or more large ones supported in a horizontal position upon others. They are found chiefly in countries inhabited by the ancient Celts, and are of a period anterior to the introduction of Christianity into these countries.
Source: Webster's dictionaryThe cromlechs most worthy of notice are: one near Cairngrainey, to the north-east of the old road from Belfast to Templepatrick ; the large cromlech at Mount Druid, near Ballintoy ; and one at the northern extremity of Islandmagee. Source: Internet
OED "Dolmen", 1st edition, 1897 Nonetheless it has now replaced cromlech as the usual English term in archaeology, when the more technical and descriptive alternatives are not used. Source: Internet