Definition of oculus in English:


Pronunciation /ˈäkyələs/ /ˈɑkjələs/


  • 1Architecture
    A round or eye-like opening or design.

    ‘Either way, feeding a signal from a microphone placed in the oculus gives a real audio picture of the size of the space.’
    • ‘What could have swayed Capponi away from the plan for an oculus and toward the tall, narrow shape employed by Marcillat?’
    • ‘Vents in the facade, the cupolas, and the oculi inside allowed air to circulate throughout the building.’
    • ‘Each of the upper study areas has an oculus in the floor revealing its counterpart below.’
    1. 1.1A circular window.
      ‘The oculus windows depicted in each of their two cells illuminate the figures with an otherworldly silvery light.’
      • ‘The sun streams in through the open oculus, tracing a circular disk across the walls and floor, creating a walk-in solar observatory.’
      • ‘The oculus window will complement two large stained glass windows that have been installed in the third-floor ceiling.’
      • ‘A large oculus brings a cylinder of light down into the main library, bathing the interior in a softly luminous glow.’
      • ‘The light entering through the oculus at the top floods the space with hypnotic patterns of light and shadow.’
    2. 1.2The central boss of a volute.
      • ‘Formed by the intersection of toroidal geometries, the roof is composed of two shells that interlock at the centre of which is a great glass oculus.’
    3. 1.3An opening at the apex of a dome.
      ‘At the top of the columns a concrete-on-steel deck platform forms the oculus of the interior dome.’
      • ‘Supported by slender steel columns that splay arboreally at their tops, the concrete canopy is perforated by a series of different-sized oculi.’
      • ‘The major interior space, the Potomac rotunda, balloons under a domed ceiling with an oculus, reaching a height of 120 feet.’
      • ‘A round stained glass window will be installed above the oculus (opening at the top of the dome).’
      • ‘At the centre of the dome is an oculus, a circular hole, which is the only source of light.’


Mid 19th century from Latin, literally ‘eye’.