Editing Oculus (architecture) (section)

{{Short description|Circular opening in the center of a dome or in a wall}}
{{Redirect|Oculi|the third Sunday in Lent|Lent{{!}}Oculi Sunday}}
[[File:Paris - Palais du Louvre - PA00085992 - 226 (oculus cropped).jpg|thumb|upright=1.35|[[Renaissance architecture|Renaissance]] oculus on the west facade of the [[Cour Carrée]] of the [[Louvre Palace]], with figures of war and peace, sculpted by [[Jean Goujon]] and designed by [[Pierre Lescot]], 1548<ref>{{cite book|last=Bresc-Bautier|first=Geneviève|title=The Louvre, a Tale of a Palace|date=2008|publisher=Musée du Louvre Éditions|isbn=978-2-7572-0177-0|page=122|url=}}</ref>]]

An '''oculus''' ({{etymology|la|{{wikt-lang|la|oculus}}|eye}}; {{plural abbr|'''oculi'''}}) is a circular opening in the center of a [[dome]] or in a wall. Originating in [[classical architecture]], it is a feature of [[Byzantine architecture|Byzantine]] and [[Neoclassical architecture]]. 

A horizontal oculus in the center of a dome is also called '''opaion''' ({{etymology|grc|''{{wikt-lang|grc|ὀπαῖον}}'' ({{grc-transl|ὀπαῖον}})|(smoke) hole}}; {{plural abbr|'''opaia'''}}).