aperture

American  

[ap-er-cher] / ˈæp ər tʃər /

noun

1. an opening, as a hole, slit, crack, gap, etc.

2. Also called aperture stop.  Optics.  an opening, usually circular, that limits the quantity of light that can enter an optical instrument.

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aperture British  

/ ˈæpətʃə /

noun

1. a hole, gap, crack, slit, or other opening

2. physics

   1. a usually circular and often variable opening in an optical instrument or device that controls the quantity of radiation entering or leaving it

   2. the diameter of such an opening See also relative aperture

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Other Word Forms

• apertural adjective
• apertured adjective

Etymology

Origin of aperture

1400–50; late Middle English < Latin apertūra an opening, equivalent to apert ( us ) opened (past participle of aperīre; aper ( i )- ( aperient ) + -tus past participle suffix) + -ūra -ure

Example Sentences

The latest version, made by ASML, performs high numerical aperture extreme ultraviolet lithography.

From The Wall Street Journal

Squeezing through its aperture, it’s easy to reflect on the winnowing that happens at the end of our days, as physical, mental and other abilities slowly fade.

From The Wall Street Journal

A camera’s aperture widens during filming to capture the full spectacle.

From Salon

When Elwood meets Turner, Ross begins to switch between their vantage points, widening the film’s emotional aperture in the process.

From Salon

I currently still have an aperture, which means a tear above my cords.

From Los Angeles Times