aperture
- Noun. An opening; an open space; a gap, cleft, or chasm; a passage perforated; a hole; as, an aperture in a wall.
- Noun. (optics) Something which restricts the diameter of the light path through one plane in an optical system.
- Noun. (context, astronomy) 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.
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This entry was last updated on RefTopia from its source on 3/20/2012.