acceleration

American  

[ak-sel-uh-rey-shuhn, ik-] / ækˌsɛl əˈreɪ ʃən, ɪk- /

noun

1. the act of accelerating; increase of speed or velocity.

2. a change in velocity.

3. Mechanics. the time rate of change of velocity with respect to magnitude or direction; the derivative of velocity with respect to time.

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acceleration British  

/ ækˌsɛləˈreɪʃən /

noun

1. the act of accelerating or the state of being accelerated

2.  a.  the rate of increase of speed or the rate of change of velocity

3.  a.  the power to accelerate

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acceleration Scientific  

/ ăk-sĕl′ə-rā′shən /

1. The rate of change of the velocity of a moving body. An increase in the magnitude of the velocity of a moving body (an increase in speed) is called a positive acceleration; a decrease in speed is called a negative acceleration. Acceleration, like velocity, is a vector quantity, so any change in the direction of a moving body is also an acceleration. A moving body that follows a curved path, even when its speed remains constant, is undergoing acceleration.

2. See more at gravity relativity

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acceleration Cultural  

1. A change in the velocity of an object.

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Discover More

The most familiar kind of acceleration is a change in the speed of an object. An object that stays at the same speed but changes direction, however, is also being accelerated. (See force.)

Other Word Forms

Derived Forms

• nonacceleration
  noun
• reacceleration
  noun
• overacceleration
  noun

Etymology

Origin of acceleration

First recorded in 1525–35, acceleration is from the Latin word accelerātiōn- (stem of accelerātiō ). See accelerate, -ion

Explanation

Acceleration is the act of increasing speed. When you buy a sports car, you want one that has great acceleration, so it can go from zero to 60 miles an hour in no time. Acceleration comes from the Latin word accelerationem, which means "a hastening." When you hasten, you hurry, so acceleration is a speeding-up. Maybe you are walking to an appointment and realize you will be late. You pick up your pace — that's acceleration. If the rain on a stormy day begins to come down faster, that too is acceleration. As you can see, acceleration isn't just for cars.

Example Sentences

"The origins and acceleration mechanisms of ultrahigh-energy cosmic rays have been among the biggest mysteries in the field for more than 60 years, since the first example was reported," Murase said.

From Science Daily • Jun. 9, 2026

Importantly, hourly earnings came in exactly on forecast — no acceleration at all.

From MarketWatch • Jun. 6, 2026

If the car in front is struggling with rear tyre wear, and is therefore limited on grip during acceleration, that, combined with overtake mode, just might make them vulnerable to the car behind.

From BBC • Jun. 3, 2026

“We are squarely in the acceleration phase of the AI era,” said Kevin Shea, senior equity strategist at BNY Wealth.

From The Wall Street Journal • Jun. 1, 2026

The acceleration dragged at her body with invisible hands, stretching the flesh over her arms and face.

From "Artemis Fowl" by Eoin Colfer