Arch. Pl. culs-de-four. [F. = furnace bottom, oven bottom.] (See quots.)
1727–51. Chambers, Cycl., Cul de four, a sort of low, spherical vault, oven-like…. Cul de four of a niche, denotes the arched roof of a niche on a circular plan.
1876. Gwilt, Archit., Gloss., Cul de four, a low vault spherically formed on a circular or oval plan. An oven-shaped vault.
