decelerate

verb

de·​cel·​er·​ate (ˌ)dē-ˈse-lə-ˌrāt 

decelerated; decelerating

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 

noun

decelerator

(ˌ)dē-ˈse-lə-rā-tər 

noun

Synonyms

• slow
• brake

Examples of decelerate in a Sentence

she decelerated the car as we entered the school zone

Recent Examples on the Web

Its unusual construction, featuring fewer panels than any ball before or since, meant a lack of ‘drag’, so the ball didn’t decelerate properly, and moved unpredictably late. —Michael Cox, New York Times, 16 Aug. 2025

Furniture price growth picked up in July, while apparel price growth decelerated and appliance prices declined outright. —Rob Wile, NBC news, 12 Aug. 2025

Analysts have expressed concern that PC demand will decelerate after a strong first half. —Bloomberg, Mercury News, 25 July 2025

And for the third quarter, the Atlanta Fed’s GDP tracker points to growth decelerating to 2.1%. —Jason Ma, Fortune, 2 Aug. 2025

Word History

Etymology

de- + accelerate

First Known Use

1899, in the meaning defined at transitive sense 1

Rhymes for decelerate

• abbreviate
• accelerate
• accommodate
• accumulate
• acuminate
• adjudicate
• adulterate
• affiliate
• agglomerate
• agglutinate
• alleviate
• amalgamate

Kids Definition

decelerate

verb

de·​cel·​er·​ate (ˈ)dē-ˈsel-ə-ˌrāt 

decelerated; decelerating

: to move or cause to move at decreasing speed : slow down

deceleration

(ˌ)dē-ˌsel-ə-ˈrā-shən 

noun

decelerator

(ˈ)dē-ˈsel-ə-ˌrāt-ər 

noun

Medical Definition

decelerate

verb

de·​cel·​er·​ate (ˈ)dē-ˈsel-ə-ˌrāt 

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 

noun