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[dee-sel-uh-reyt] /diˈsɛl əˌreɪt/
verb (used with object), decelerated, decelerating.
to decrease the velocity of:
He decelerates the bobsled when he nears a curve.
to slow the rate of increase of:
efforts to decelerate inflation.
verb (used without object), decelerated, decelerating.
to slow down:
The plane decelerated just before landing.
Origin of decelerate
1895-1900; de- + (ac)celerate
Related forms
deceleration, noun
decelerator, noun
nondeceleration, noun Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for deceleration
  • It occurs when there is a sudden acceleration or deceleration of the head, a process depicted here in this animation.
  • Those precise observations only confirm the expected deceleration of the universe.
  • Not taking into account acceleration and deceleration times plus time to explore the target system.
  • Only since then has there been the surprising deceleration in wage growth.
  • As these examples indicate, a deceleration need not precipitate disaster.
  • But the pace of the deceleration has begun to raise concerns.
  • At the time it was a disappointment because it was a sharp deceleration from prior decades.
  • deceleration levels were initiated by the driver through the standard braking system of the vehicle.
  • Near the bottom of the figure, a deceleration lane tapers to the right of the right lane, leading to a right exit ramp.
  • The deceleration lane runs parallel to the through lanes and is separated from them by a dotted and then broken white line.
British Dictionary definitions for deceleration


to slow down or cause to slow down
Derived Forms
deceleration, noun
decelerator, noun
Word Origin
C19: from de- + accelerate
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
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Word Origin and History for deceleration

1894, originally in railroading, coined from de- "do the opposite of" (see de-) + (ac)celeration.

Verily "deceleration" is a word which could only be coined by the Great Western. ["Engineering," Feb. 2, 1894]



1899, back-formation from deceleration. Related: Decelerated; decelerating.

Online Etymology Dictionary, © 2010 Douglas Harper
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