Carol (quadril, from its square shape, quarree, through the Norman word carole), as an architectural term, is
(1) a grille, cage, closure, or chancel; railings round the tombs of martyrs or persons of sanctity or importance; a screen of wood or metal, designed to preserve them from indiscreet devotion by pilgrims, and from injury by ignorant or mischievous visitors. They are frequently mentioned in the inventory of St. Paul's, London. The confession in the basilica was always fenced with a balustrade of this kind.
(2) An enclosed study or reading-place in a cloister, used by the scribes or ordinary monks and regular canons. Carols of stone remain in the cloisters of Beaulieu, Melrose, and Gloucester, the south and west walks at Clester the south and east walks at Worcester, and were in the south alley of Canterbury. At Durham there are three carols in each window; at Worcester apertures for communication remain between the recesses. In foreign monasteries they are usually placed in the little cloisters.