refraction(redirected from sight-testing)
Also found in: Thesaurus, Medical, Encyclopedia.
refraction of light
i: angle of incidence
r: angle of refraction
1. The deflection of a wave, such as a light or sound wave, when it passes obliquely from one medium into another having a different index of refraction.
2. Astronomy The apparent change in position of a celestial object caused by the bending of light rays as they enter Earth's atmosphere.
a. The ability of the eye to bend light so that an image is focused on the retina.
b. Determination of this ability in an eye.
re·frac′tion·al, re·frac′tive adj.
re·frac′tive·ness, re′frac·tiv′i·ty (rē′frăk-tĭv′ĭ-tē) n.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
1. (General Physics) physics the change in direction of a propagating wave, such as light or sound, in passing from one medium to another in which it has a different velocity
2. (General Physics) the amount by which a wave is refracted
3. (Physiology) the ability of the eye to refract light
4. (Medicine) the determination of the refractive condition of the eye
5. (Astronomy) astronomy the apparent elevation in position of a celestial body resulting from the refraction of light by the earth's atmosphere
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
1. the change of direction of a ray of light, sound, heat, or the like, in passing obliquely from one medium into another in which its wave velocity is different.
a. the ability of the eye to refract light that enters it so as to form an image on the retina.
b. the determining of the refractive condition of the eye.
3. the amount, in angular measure, by which the altitude of a celestial body is increased by the refraction of its light in the earth's atmosphere.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
Light waves bend as they pass from one substance to another. This pencil appears to be bent at various angles as the light passes through air only; through air and glass; through water, air, and glass; and through water and glass.
1. The bending or turning of a wave, such as a light or sound wave, when it passes from one medium to another medium of different density. See more at wave. Compare reflection.
2. The apparent change in position of a celestial body caused by the bending of light as it enters the Earth's atmosphere.
Usage The words refraction and reflection describe two different ways that a light wave, sound wave, or other wave can move when it encounters a boundary between two media. The media can be two different substances, such as glass and air, or they can be regions of a single substance that are in different states, such as regions of air that are at different temperatures. Reflection occurs when a wave hits the boundary and returns immediately to its original medium. Refraction occurs when a wave passes from one medium to another and is bent; that is, the wave deviates from the straight-line path it would have otherwise followed. For example, light passing through a prism is bent when it enters the prism and again when it leaves the prism. The light is therefore refracted. Light striking a mirror bounces off the silver backing without entering it. The light is therefore reflected. The boundary between the media does not have to be abrupt for reflection or refraction to occur. On a hot day, the air over the surface of an asphalt road is warmer than the air above it. Because light travels at different speeds in these two regions, we see an image that shimmers because its light waves are refracted.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The process by which the direction of a wave is changed when moving into shallow water at an angle to the bathymetric contours. The crest of the wave advancing in shallower water moves more slowly than the crest still advancing in deeper water, causing the wave crest to bend toward alignment with the underwater contours.
Dictionary of Military and Associated Terms. US Department of Defense 2005.
The bending of a sound wave or ray of light as it passes from one medium to another.
Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited
Switch to new thesaurus
|Noun||1.||refraction - the change in direction of a propagating wave (light or sound) when passing from one medium to another|
physical phenomenon - a natural phenomenon involving the physical properties of matter and energy
|2.||refraction - the amount by which a propagating wave is bent|
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
refraction[rɪˈfrækʃən] N → refracción f
Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005
refraction[rɪˈfrækʃən] n [light, ray, wave] → réfraction f
Collins English/French Electronic Resource. © HarperCollins Publishers 2005
Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007
refraction[rɪˈfrækʃ/ən] n → rifrazione f
Collins Italian Dictionary 1st Edition © HarperCollins Publishers 1995
n. refracción, acto de refractar;
ocular ___ → ___ ocular.
English-Spanish Medical Dictionary © Farlex 2012
refractionn refracción f
English-Spanish/Spanish-English Medical Dictionary Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.