center of mass

American  

noun

Mechanics.

1. the point at which the entire mass of a body may be considered concentrated for some purposes; formally, the point such that the first moment of a physical or geometric object about every line through the point is zero.

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center of mass Scientific  

1. A point in space determined by a distribution of mass (such as a solid object, a collection of objects, or a gas), such that a uniform force acting on the whole distribution acts as if the distribution were located at just that point. For example, the gravitational force on Earth attracts small objects as if it were pulling them from their center of mass (in this case, the center of mass is also called the center of gravity). Two stars in orbit around each other revolve around their collective center of mass.

2. See also barycenter

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Etymology

Origin of center of mass

First recorded in 1875–80

Compare meaning

How does center-of-mass compare to similar and commonly confused words? Explore the most common comparisons:

• center of mass vs. center of gravity

Example Sentences

See Examples For:

center of mass

Scientists have spent decades developing methods to define and locate Earth's center of mass using observations from space.

From Science Daily ● Oct. 7, 2026

Researchers used a model created by the European Centre for Medium-Range Weather Forecasts to estimate how seasonal atmospheric changes alter Earth's center of mass.

From Science Daily ● Oct. 7, 2026

Co-founder Yuzhe Qin said the battery and electronics go into the base, which gives it a low center of mass.

From The Wall Street Journal ● Jul. 4, 2026

The two asteroids orbit a shared center of mass in what scientists call a binary system.

From Science Daily ● Mar. 9, 2026

Seven mighty green tractors would lash out, seize an attacking sphere, and snap it into the center of mass of the unit of seven.

From Spacehounds of IPC by E. E. (Edward Elmer) Smith