aperture
UK /ˈap.ə.t͡ʃə/ · US /ˈæp.ɚˌt͡ʃʊɹ/ noun
Forms apertures
- noun A small or narrow opening, gap, slit, or hole. “an aperture in a wall”
- noun (optics) A hole which restricts the diameter of the lightpath through one plane in an optical system.
- noun (astronomy, photography) The diameter of such a hole which restricts the width of the lightpath through the whole system. For a telescope, this is the diameter of the objective lens. “This telescope has a 100 cm aperture.”
- noun (space flight, communication) The (typically) large-diameter antenna used for receiving and transmitting radio frequency energy containing the data used in communication satellites, especially in the geostationary belt. For a comsat, this is typically a large reflective dish antenna; sometimes called an array.
- noun (mathematics, rare, of a right circular cone) The maximum angle between the two generatrices. “If the generatrix makes an angle θ to the axis, then the aperture is 2θ.”
Synonyms
Etymology
From late Middle English, from Latin apertūra (“an opening”), from aperiō (“to uncover, make or lay bare”) + -tūra (“-ure”, action noun suffix). Doublet of overture and apertura.
Webster’s 1913
- noun The act of opening. [Obs.]
- noun An opening; an open space; a gap, cleft, or chasm; a passage perforated; a hole; as, an aperture in a wall.
Etymology [L. apertura, fr. aperire. See Aperient.]
Sources: Wiktionary · Webster’s 1913 — from the Wiktionary entry “aperture”, CC BY-SA 4.0. Details