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

Sorge said that this class of space debris decelerates quicker, and also once on the surface the pieces are also more recognizable than broken up chunks of metal. — Leonard David, Space.com, 22 July 2026

That fueled fears that on a per-user basis, Netflix’s engagement is decelerating, indicating headwinds for subscription and ad revenue growth. — Todd Spangler, Variety, 17 July 2026

In June, wholesale inflation is expected to have decelerated slightly. — Sarah Min, CNBC, 10 July 2026

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

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