aperture

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.

• (Received Pronunciation) IPA^(key): /ˈap.ə.t͡ʃə/, /ˈap.ə.tjʊə/

  • Audio (Southern England)

    (file)

• (General American) IPA^(key): /ˈæp.ɚˌt͡ʃʊɹ/, /ˈæp.ɚ.t͡ʃɚ/, /ˈæp.ɚˌtjʊɹ/, /ˈæp.ɚˌtʊɹ/
• Rhymes: -æpə(ɹ)tʃə(ɹ), -æpə(ɹ)tjʊə(ɹ), -æpə(ɹ)tʃʊə(ɹ)

aperture (plural apertures)

1. A small or narrow opening, gap, slit, or hole.

   an aperture in a wall

   Hyponym: piriform aperture

   • 1859, Richard Owen, On the Classification and Geographical Distribution of the Mammalia, London: J. W. Parker and Son, page 29:

     Were the larynx of the little creature like that of the parent, the milk might—probably would—enter the windpipe and cause suffocation : but the fœtal larynx is cone-shaped, with the opening at the apex, which projects, as in the whale-tribe, into the back aperture of the nostrils, where it is closely embraced by muscles of the ‘soft palate.’

   • 1860, Samuel Hannaford, chapter 7, in Sea and River-side Rambles in Victoria, page 53:

     In the centre of the fleshy membrane is an aperture leading into a deep cavity, at the bottom of which is placed a prominent piston that may be retracted by muscular fibres provided for the purpose.

   • 1897, Richard Marsh, The Beetle:

     The door was opened — ‘on the chain.’ The old lady peered at us through an aperture of about six inches.

2. (optics) A hole which restricts the diameter of the lightpath through one plane in an optical system.
   1. (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.

      Hyponym: angular aperture

      This telescope has a 100 cm aperture.

3. (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.
4. (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.

• The aperture of microscopes is often expressed in degrees, called also the angular aperture, which signifies the angular breadth of the pencil of light which the instrument transmits from the object or point viewed; as, a microscope of 100° aperture.

• “aperture”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.
• “aperture”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.

• “aperture”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.
• “aperture”, in The Century Dictionary […], New York, N.Y.: The Century Co., 1911, →OCLC.

Borrowed from Latin apertūra (“opening”). Doublet of ouverture.

• IPA^(key): /a.pɛʁ.tyʁ/

• Audio

  (file)

aperture f (uncountable)

1. (phonetics, phonology) opening, openness, aperture

• apéritif
• ouvrir

• “aperture”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012.

• IPA^(key): /a.perˈtu.re/
• Rhymes: -ure
• Hyphenation: a‧per‧tù‧re

aperture f

1. plural of apertura

• reputare, reputerà

apertūre

1. vocative masculine singular of apertūrus

aperture

1. inflection of aperturar:
   1. first/third-person singular present subjunctive
   2. third-person singular imperative