aperture

Universal Words noun 1 (formal) a small opening in sth: The soldier fired the rifle through a narrow aperture in a pile of sandbags. 2 (technical) an opening that allows light to reach a LENS, especially in cameras: For flash photography, set the aperture at f.5.6. * Open up the lens aperture to maximize the brightness of the shot. * Binoculars of this aperture are very expensive.