Lunette

(1) In Fortification, a work with two faces and two flanks, i. e. a Redan to which flanks or lateral wings have been added; in form, therefore, it resembles a Bastion. (2) In Architecture, a crescent or semicircular window, or space above a square window beneath a rounded roof. Hence the paintings on such a space are called lunettes; e. g. those of Raffaelle in the Vatican.