cromlech

n. [ W. cromlech; crom bending or bent, concave + llech a flat stone; akin to Ir. cromleac. ] (Archæol.) 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. [ 1913 Webster ]