viscosity

American  

[vi-skos-i-tee] / vɪˈskɒs ɪ ti /

noun

plural

viscosities

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

• hyperviscosity noun

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

This finding suggests that viscosity, or a liquid's resistance to flow, plays a much larger role in its mechanical behavior than scientists previously believed.

From Science Daily • Mar. 30, 2026

“It’s a rich, thick vanilla. I like the viscosity of it.”

From The Wall Street Journal • Dec. 1, 2025

I loved its viscosity, that rich, luxurious texture that clung to everything it touched, enveloping everything it's heaped over.

From Salon • Jun. 5, 2025

He said it could allow scientists "to make more informed estimates of some important material properties, such as the viscosity of the inner core, which is one of the least known quantities in modern science".

From BBC • Feb. 10, 2025

She seems unaffected by the newfound viscosity in the air.

From "Kwame Crashes the Underworld" by Craig Kofi Farmer