OCULUS

:''This page is about the architectural term. See also: eye.''



'Oculus' (pl. oculi) is the Latin word for eye, and the word remains in use in certain contexts, most commonly as the name of the round opening in the top of the dome of the Pantheon in Rome, Italy, and less often in reference to other round windows. The Oculus in the Pantheon is and has always been open to the weather, allowing rain to enter and fall to the floor, from where it is carried away through drains. In the picture, right, sunlight streams through the opening and strikes the lower part of the dome. The bright opening and the surrounding smooth concrete above the coffering resembles an eye, giving the opening its name.
While ''oculus'' is not in common use in English, words derived from it such as ocular (relating to the eye) are, primarily in medical and optical fields. Also, the terms ''Oculus Dexter'' (right eye), ''Oculus Sinister'' (left eye), and ''Oculus Uterque'' (both eyes) are used in medicine, usually abbreviated 'OD', 'OS', and 'OU', respectively.
In archaeology, 'oculus' is the name of a motif found in western European prehistoric art. It consists of a pair of circular or spiral marks, often interpreted as eyes, and appears on pottery, statues and megaliths. It may represent the watchful gaze of a god or goddess (see dolmen deity for example) and was especially common during the Neolithic period.