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 of decelerate

• slow
• brake

Examples of decelerate in a Sentence

she decelerated the car as we entered the school zone

Recent Examples on the Web

Analysts cited yesterday's mixed quarter and decelerating comps. —Jim Cramer, CNBC, 11 Mar. 2026

Most measures also indicate national wage growth is decelerating, even as some pockets of the labor market that are most reliant on immigrants, like construction and traveler accommodation, are registering faster pay increases. —Bloomberg, Mercury News, 10 Mar. 2026

China’s decelerating economic growth has not significantly curbed its military spending. —John Liu, CNN Money, 5 Mar. 2026

After your tires regain traction, continue to decelerate your vehicle and avoid coming to an abrupt stop. —Charles Singh, USA Today, 24 Feb. 2026

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