Poisson's ratio

American  

Or Poisson ratio

noun

Physics.

1. the ratio, in an elastic body under longitudinal stress, of the transverse strain to the longitudinal strain.

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Poisson's ratio British  

noun

1.  μ.   ν.  a measure of the elastic properties of a material expressed as the ratio of the fractional contraction in breadth to the fractional increase in length when the material is stretched

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Etymology

Origin of Poisson's ratio

First recorded in 1925–30; see origin at Poisson distribution

Example Sentences

See Examples For:

Poisson's ratio

Even though the inner core is solid, it behaves like a softened metal, slowing seismic shear waves and displaying a Poisson's ratio more similar to butter than to steel.

From Science Daily ● Dec. 10, 2025

By pairing in-situ sound velocity measurements with advanced molecular dynamics simulations, the team detected a dramatic loss of shear wave speed and a sharp increase in Poisson's ratio.

From Science Daily ● Dec. 10, 2025

Auxetics have a negative value of Poisson's ratio and do exactly the reverse.

From Science Daily ● Jun. 4, 2024

Most materials have a positive Poisson's ratio, which means squeezing them in one direction will make them wider and/or thicker in other directions.

From Science Daily ● Jun. 4, 2024

The Poisson’s ratio depends upon the direction of the contracted lateral filaments as well as upon that of the longitudinal extended ones.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 2 "Ehud" to "Electroscope" by Various