critical angle

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noun

Optics. the minimum angle of incidence beyond which total internal reflection occurs for light traveling from a medium of higher to one of lower index of refraction; the angle of incidence for which refracted rays emerge tangent to the surface separating two media, the light traveling from the medium of higher to the medium of lower index of refraction.

Also called angle of stall, critical angle of attack, stalling angle. Aeronautics. the angle of attack, greater than or equal to the angle of attack for maximum lift, at which there is a sudden change in the airflow around an airfoil with a subsequent decrease in lift and increase in drag.

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Origin of critical angle

First recorded in 1870–75

Words nearby critical angle

criteria, criterion, crithidia, critic, critical, critical angle, critical apparatus, critical care unit, critical constant, critical constants, critical damping

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use critical angle in a sentence

Dossi initially was listed in critical condition with wounds to his arm and lower back.
Shot Down During the NYPD Slowdown|Michael Daly|January 7, 2015|DAILY BEAST
My captain on the boat, Brazakka, he wanted me to do this Hemingway bit, with the white stubble, and he wanted the hero angle.
The Story Behind Lee Marvin’s Liberty Valance Smile|Robert Ward|January 3, 2015|DAILY BEAST
Dear Thief is worthy of the abused critical adjectives philosophical, atmospheric, and masterful.
A Novel Nearly Impossible to Review|Nicholas Mancusi|December 28, 2014|DAILY BEAST
But by the time a critical wanted poster sent via fax arrived, more than two hours elapsed.
Alleged Cop Killer Ismaaiyl Brinsley Had a Death Wish|M.L. Nestel|December 22, 2014|DAILY BEAST

Truth is, no one is sure how Cuba will play in the critical swing state of Florida in 2016.
How Will Cuba Play In Peoria?|Eleanor Clift|December 21, 2014|DAILY BEAST
These are few and verbal, but momentous, and were not made without consultation of many critical authorities and versions.
Solomon and Solomonic Literature|Moncure Daniel Conway
In the centre of many of the rooms there played a small fountain; in others there were four, one in each angle.
Blackwood's Edinburgh Magazine, Volume 60, No. 372, October 1846|Various
The Colonel left, and in a few days the election coming off, each candidate made his appearance at the critical German polls.
The Book of Anecdotes and Budget of Fun;|Various
The rest is done by cutting away two upper and four under-teeth, and substituting false ones at the desired angle.
Checkmate|Joseph Sheridan Le Fanu
He was threatened with erysipelas, and there was a rather critical inflammation of the left eye.
Checkmate|Joseph Sheridan Le Fanu

British Dictionary definitions for critical angle

critical angle

noun

the smallest possible angle of incidence for which light rays are totally reflected at an interface between substances of different refractive index

another name for stalling angle

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for critical angle

critical angle

[ krĭt′ĭ-kəl ]

The smallest angle of incidence at which radiation, such as light, is completely reflected from the boundary between two media. At angles smaller than the critical angle, some of the radiation enters the second material and is refracted.