decelerate

verb

de·​cel·​er·​ate (ˌ)dē-ˈse-lə-ˌrāt How to pronounce decelerate (audio)
decelerated; decelerating
Synonyms of deceleratenext

transitive verb

1
: to reduce the speed of : slow down
decelerate a car
2
: to decrease the rate of progress of
decelerate growth
decelerate soil erosion

intransitive verb

: to move at decreasing speed
deceleration
(ˌ)dē-ˌse-lə-ˈrā-shən How to pronounce decelerate (audio)
noun
decelerator
(ˌ)dē-ˈse-lə-rā-tər How to pronounce decelerate (audio)
noun

Synonyms of decelerate

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Examples of decelerate in a Sentence

she decelerated the car as we entered the school zone
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
And unlike hitting a tree or another car, impact with a moose typically doesn’t cause the car to decelerate fast enough to trigger airbags. — Mack Degeurin, Popular Science, 18 June 2026 Nvidia’s growth outlook, while still strong, is expected to decelerate in the coming years, which could further impede the stock’s momentum. — Bloomberg, Mercury News, 20 May 2026 The premium multiple that Apple trades on requires a services business that continues to grow at high rates, and that growth has been decelerating. — Jason Kirsch, Forbes.com, 11 May 2026 Even hundreds of miles above the Earth, trace wisps of high atmosphere exert a subtle drag on orbiting objects, slowly decelerating them and eventually pulling them down out of the sky. — Jeffrey Kluger, Time, 16 Apr. 2026 See All Example Sentences for decelerate

Word History

Etymology

de- + accelerate

First Known Use

1899, in the meaning defined at transitive sense 1

Time Traveler
The first known use of decelerate was in 1899

Rhymes for decelerate

See All Rhymes for decelerate

Browse Nearby Words

deceivingly
decelerate
deceleration
See all Nearby Words

Cite this Entry

“Decelerate.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/decelerate. Accessed 7 Jul. 2026.

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Kids Definition

decelerate

verb
de·​cel·​er·​ate (ˈ)dē-ˈsel-ə-ˌrāt How to pronounce decelerate (audio)
decelerated; decelerating
: to move or cause to move at decreasing speed : slow down
deceleration
(ˌ)dē-ˌsel-ə-ˈrā-shən How to pronounce decelerate (audio)
noun
decelerator
(ˈ)dē-ˈsel-ə-ˌrāt-ər How to pronounce decelerate (audio)
noun

Medical Definition

decelerate

verb
de·​cel·​er·​ate (ˈ)dē-ˈsel-ə-ˌrāt How to pronounce decelerate (audio)
decelerated; decelerating

transitive verb

: to reduce the speed of : slow down

intransitive verb

: to move at decreasing speed
deceleration
(ˌ)dē-ˌsel-ə-ˈrā-shən How to pronounce decelerate (audio)
noun

More from Merriam-Webster on decelerate

Nglish: Translation of decelerate for Spanish Speakers

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