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Webster 1913 Edition


Aperture

Ap′er-ture

(?; 135)
,
Noun.
[L.
apertura
, fr.
aperire
. See
Aperient
.]
1.
The act of opening.
[Obs.]
2.
An opening; an open space; a gap, cleft, or chasm; a passage perforated; a hole;
as, an
aperture
in a wall
.
An
aperture
between the mountains.
Gilpin.
The back
aperture
of the nostrils.
Owen.
3.
(Opt.)
The diameter of the exposed part of the object glass of a telescope or other optical instrument;
as, a telescope of four-inch
aperture
.
☞ 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.

Webster 1828 Edition


Aperture

AP'ERTURE

, n.
1.
The act of opening; more generally, an opening; a gap, cleft or chasm; a passage perforated; a hole through any solid substance.
2.
An opening of meaning; explanation. [Not used.]
3.
In geometry, the space between two right lines, forming an angle.

Definition 2024


aperture

aperture

See also: aperturé

English

Noun

aperture (plural apertures)

  1. An opening; an open space; a gap, cleft, or chasm; a passage perforated; a hole; as, an aperture in a wall.
    • Gilpin
      an aperture between the mountains
    • Owen
      the back aperture of the nostrils
  2. (optics) Something which restricts the diameter of the light path through one plane in an optical system.
  3. (astronomy, photography) The diameter of the aperture (in the sense above) which restricts the width of the light path through the whole system. For a telescope, this is the diameter of the objective lens. e.g. a telescope may have a 100 cm aperture.
  4. (spaceflight, 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.
  5. (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.

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


External links

  • aperture in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913
  • aperture in The Century Dictionary, The Century Co., New York, 1911

Italian

Noun

aperture f

  1. plural of apertura

Anagrams


Latin

Participle

apertūre

  1. vocative masculine singular of apertūrus

Spanish

Verb

aperture

  1. First-person singular (yo) present subjunctive form of aperturar.
  2. Formal second-person singular (usted) present subjunctive form of aperturar.
  3. Third-person singular (él, ella, also used with usted?) present subjunctive form of aperturar.
  4. Formal second-person singular (usted) imperative form of aperturar.