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

Inflation remains much higher than anyone would like, but reports earlier this week suggested the pace of increases in prices is decelerating. — Stan Choe, Los Angeles Times, 14 Aug. 2026

When the one sector doing the work starts decelerating, the arithmetic gets unforgiving quickly. — Jason Kirsch, Forbes.com, 12 Aug. 2026

Apple also said services growth would decelerate in the September quarter. — Bloomberg, Mercury News, 31 July 2026

Hitting the brakes Altman isn’t the only one talking about decelerating AI. — Beatrice Nolan, Fortune, 30 July 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