aperture

== English == === 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. === Pronunciation === (Received Pronunciation) IPA(key): /ˈap.ə.t͡ʃə/, /ˈap.ə.tjʊə/ (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) === Noun === aperture (plural apertures) A small or narrow opening, gap, slit, or hole. Hyponym: piriform aperture (optics) A hole which restricts the diameter of the lightpath through one plane in an optical system. (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 (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. (mathematics, rare, of a right circular cone) The maximum angle between the two generatrices. ==== Usage notes ==== 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. ==== Derived terms ==== ==== Related terms ==== ==== Translations ==== === References === “aperture”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022. “aperture”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present. === Further reading === “aperture”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC. William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “aperture”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC. == French == === Etymology === Borrowed from Latin apertūra (“opening”). Doublet of ouverture. === Pronunciation === IPA(key): /a.pɛʁ.tyʁ/ === Noun === aperture f (uncountable) (phonetics, phonology) opening, openness, aperture ==== Related terms ==== apéritif ouvrir === Further reading === “aperture”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012 == Italian == === Pronunciation === IPA(key): /a.perˈtu.re/ Rhymes: -ure Hyphenation: a‧per‧tù‧re === Noun === aperture f plural of apertura === Anagrams === reputare, reputerà == Latin == === Participle === apertūre vocative masculine singular of apertūrus == Spanish == === Verb === aperture inflection of aperturar: first/third-person singular present subjunctive third-person singular imperative