  an oculus, plural oculi, from latin oculus: eye, denotes a circular opening in the centre of a dome or in a wall. originating in antiquity, it is a feature of byzantine and neoclassical architecture. it is also known as an Åil de boeuf from the french, or simply a "bull's-eye"."oculus window". royal institute of british architects. retrieved 24 january 2013. ==classical example== the oculus was used by the romans, one of the finest examples being that in the dome of the pantheon. open to the weather, it allows rain to enter and fall to the floor, where it is carried away through drains. though the opening looks small, it actually has a diameter of  allowing it to light the building just as the sun lights the earth. the rain also keeps the building cool during the hot summer months."oculus of the pantheon", about.com. retrieved 24 january 2013. ==byzantine architecture== the oculus was widely used in the architecture of the byzantine empire. it was applied to buildings in syria in the 5th and 6th centuries and again in the 10th century. in constantinople's myrelaion church (c.&nbsp;920), there are two oculi above the stringcourse on both lateral facades. ==neoclassical revival== early examples of the oculus in renaissance architecture can be seen in florence cathedral, in the nave clerestorey and topping the crowns of the arcade arches."the cathedral of santa maria del fiore, florence". retrieved 24 january 2013. since the revival of dome construction beginning in the italian renaissance, open oculi have been replaced by light-transmitting cupolas and other round windows, openings, and skylights. they can be seen in the pediments of palladio's villa rotonda, though not in the dome. use of oculus w
Architectural_elements Ceilings Domes Roofs Windows