verb (used with object), de·cel·er·at·ed, de·cel·er·at·ing.

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), de·cel·er·at·ed, de·cel·er·at·ing.

to slow down: The plane decelerated just before landing.

Origin of decelerate

First recorded in 1895–1900; de- + (ac)celerate
Related formsde·cel·er·a·tion, nounde·cel·er·a·tor, nounnon·de·cel·er·a·tion, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for deceleration

Historical Examples of deceleration

  • Deceleration sat on their chests and squeezed their bones to rubber.

    The K-Factor

    Harry Harrison (AKA Henry Maxwell Dempsey)

  • It would still take four hours to get down, in a spiral of deceleration.

    Space Viking

    Henry Beam Piper

  • Casker nodded and punched a deceleration spiral into the ship's tape.

    One Man's Poison

    Robert Sheckley

  • The ship quivered for just a second as it shifted over into deceleration.

  • Ekstrohm fingered loose the cinches of his deceleration couch.

British Dictionary definitions for deceleration



to slow down or cause to slow down
Derived Formsdeceleration, noundecelerator, noun

Word Origin for decelerate

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

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