viscosity

American  

[vi-skos-i-tee] / vɪˈskɒs ɪ ti /

noun

viscosities plural

1. the state or quality of being viscous.

2. Physics.

   1. the property of a fluid that resists the force tending to cause the fluid to flow.

   2. the measure of the extent to which a fluid possesses this property.

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viscosity British  

/ vɪsˈkɒsɪtɪ /

noun

1. the state or property of being viscous

2. physics

   1. the extent to which a fluid resists a tendency to flow

   2.  η.  Also called: absolute viscosity.  a measure of this resistance, equal to the tangential stress on a liquid undergoing streamline flow divided by its velocity gradient. It is measured in newton seconds per metre squared See also kinematic viscosity specific viscosity

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viscosity Scientific  

/ vĭ-skŏs′ĭ-tē /

1. The resistance of a substance to flow. For example, water has a lower viscosity than molasses and flows more easily. Viscosity is related to the concept of shear force; it can be understood as the effect of different layers of the fluid exerting shearing force on each other, or on other surfaces, as they move against each other. Viscosity lies behind the skin friction component of drag.

2. ◆ Kinematic viscosity is a measure of the rate at which momentum is transferred through a fluid. It is measured in stokes.

3. ◆ Dynamic viscosity is a measure of the ratio of the stress on a region of a fluid to the rate of change of strain it undergoes. It is equal to the kinematic viscosity times the density of the fluid. It is measured in pascal-seconds or poises.

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viscosity Cultural  

1. The internal friction of a fluid, produced by the movement of its molecules against each other. Viscosity causes the fluid to resist flowing.

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Other Word Forms

Derived Forms

• hyperviscosity
  noun

Inflected Forms

Nouns

• viscosities
  plural

Etymology

Origin of viscosity

First recorded in 1375–1425; late Middle English, from Medieval Latin viscōsitās, from Latin viscōs(us) viscous + -itās -ity

Explanation

Viscosity is the thickness of a liquid. Water flows easily. Honey does not — that's why it has greater viscosity than water. Viscosity, pronounced "vis-KOSS-ih-tee," tells you how sticky a liquid is. In the working of machines and car engines, viscosity is important. Thick oils and lubricants that have high viscosity, meaning they coat and cling, keep hard metal parts from wearing down as they rub together. Oils with dense viscosity keep machine parts from having too much friction and burning out.

Example Sentences

Viscosity usually means a measurement of how hard it is to stir -- for example, it's harder to stir a jar of honey versus a jar of water.

From Science Daily • Mar. 20, 2024

Viscosity is the resistance to flowing by a fluid.

From Textbooks • Jan. 1, 2017

Viscosity varies from one fluid to another by several orders of magnitude.

From Textbooks • Aug. 12, 2015

Through the logic of duality, this universality has a simple explanation: Viscosity is equivalent to a gravitational phenomenon, and according to Einstein’s general theory of relativity, gravitation is blind to compositional details.

From Scientific American • Dec. 18, 2012

Viscosity has a lot to do with it, too.

From The Boy with the U. S. Weather Men by Rolt-Wheeler, Francis