momentum

American  

[moh-men-tuhm] / moʊˈmɛn təm /

noun

plural

momenta, momentums

1. force or speed of movement; impetus, as of a physical object or course of events.

   The car gained momentum going downhill. Her career lost momentum after two unsuccessful films.

2. Also called linear momentum.  Mechanics. a quantity expressing the motion of a body or system, equal to the product of the mass of a body and its velocity, and for a system equal to the vector sum of the products of mass and velocity of each particle in the system.

3. Philosophy. moment.

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momentum British  

/ məʊˈmɛntəm /

noun

1.  p.  physics the product of a body's mass and its velocity See also angular momentum

2. the impetus of a body resulting from its motion

3. driving power or strength

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momentum Scientific  

/ mō-mĕn′təm /

plural

momenta

1. A vector quantity that expresses the relation of the velocity of a body, wave, field, or other physical system, to its energy. The direction of the momentum of a single object indicates the direction of its motion. Momentum is a conserved quantity (it remains constant unless acted upon by an outside force), and is related by Noether's theorem to translational invariance. In classical mechanics, momentum is defined as mass times velocity. The theory of Special Relativity uses the concept of relativistic mass. The momentum of photons, which are massless, is equal to their energy divided by the speed of light. In quantum mechanics, momentum more generally refers to a mathematical operator applied to the wave equation describing a physical system and corresponding to an observable; solutions to the equation using this operator provide the vector quantity traditionally called momentum. In all of these applications, momentum is sometimes called linear momentum.

2. See also angular momentum impulse

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momentum Cultural  

1. In physics, the property or tendency of a moving object to continue moving. For an object moving in a line, the momentum is the mass of the object multiplied by its velocity (linear momentum); thus, a slowly moving, very massive body and a rapidly moving, light body can have the same momentum. (See Newton's laws of motion.)

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Discover More

Figuratively, momentum can refer to the tendency of a person or group to repeat recent success: “The Bears definitely have momentum after scoring those last two touchdowns.”

Etymology

Origin of momentum

First recorded in 1690–1700; from Latin mōmentum; moment

Example Sentences

Yet Chisora repeatedly defied those calls, extending his career and even finding late momentum with victories over fringe world-level contenders.

From BBC • Apr. 4, 2026

New research by the Protest Project, led by sociologists Dana Fisher and Arman Azedi, suggests that No Kings is having a positive effect on encouraging political engagement, efficacy and momentum among participants.

From Salon • Apr. 4, 2026

Supported by firm commodity prices, the sector has continued to climb while other areas have struggled to maintain momentum.

From Barron's • Apr. 3, 2026

The market is expected to regain momentum later this year and current levels are viewed as attractive for accumulation.

From The Wall Street Journal • Apr. 3, 2026

Then she swings me side to side, building momentum, and finally heaves me back onto the bow, where I land hard on the deck.

From "Challenger Deep" by Neal Shusterman

Related Words

• energy
• power
• strength