momentum

noun

mo·​men·​tum mō-ˈmen-təm 

mə-

plural momenta mō-ˈmen-tə 

mə-

or momentums

1

: a property (see property sense 1a) of a moving body that the body has by virtue of its mass (see mass entry 2 sense 1c) and motion and that is equal to the product of the body's mass and velocity

broadly : a property of a moving body that determines the length of time required to bring it to rest when under the action of a constant force or moment

2

: strength or force gained by motion or by a series of events

The wagon gained momentum as it rolled down the hill.

Synonyms of momentum

• impetus
• incentive
• encouragement
• motivation
• stimulus

Examples of momentum in a Sentence

The company has had a successful year and hopes to maintain its momentum by introducing new products.

The movie loses momentum toward the end.

Recent Examples on the Web

But, at times, Yrsa’s psychological core gets lost amid the story’s momentum. — Literary Hub, 17 Sep. 2026

There is no compelling plotline to give the movie momentum, and there are slack moments when the set pieces simply don’t work. — Victor Garber, Vulture, 17 Sep. 2026

Cress added that while this type of model helicopter boasts a light, single-engine design that is usually trustworthy, the chopper’s blades can lose their momentum in rotation immediately if there is engine failure. — David Chiu, PEOPLE, 17 Sep. 2026

The light design of the rotors also means that if there is an engine failure, the light blades can lose their momentum in rotation quickly, Cress said. — Hannah Fry, Los Angeles Times, 17 Sep. 2026

Word History

Etymology

New Latin, from Latin, movement

First Known Use

1610, in the meaning defined at sense 1

Phrases Containing momentum

• angular momentum
• gather/gain momentum
• gather momentum/strength
• lose momentum
• pick up speed/momentum

Rhymes for momentum

• cementum
• omentum
• tegmentum
• tomentum
• argumentum
• sacramentum
• testamentum
• centum
• mentum

Kids Definition

momentum

noun

mo·​men·​tum mō-ˈment-əm 

plural momenta -ˈment-ə  or momentums

1

: the characteristic of a moving body that is caused by its mass and its motion

2

: impetus sense 1

Medical Definition

momentum

noun

mo·​men·​tum mō-ˈment-əm, mə-ˈment- 

plural momenta -ˈment-ə  or momentums

: a property of a moving body that the body has by virtue of its mass and motion and that is equal to the product of the body's mass and velocity

broadly : a property of a moving body that determines the length of time required to bring it to rest when under the action of a constant force