vis·​cos·​i·​ty | \ vi-ˈskä-sə-tē How to pronounce viscosity (audio) \
plural viscosities

Definition of viscosity

1 : the quality or state of being viscous : a sticky or glutinous consistency
2a technical : the property of resistance to flow in any material with fluid properties … water has a small but measurable viscosity, or "stickiness," which results from the weak mutual attraction of water molecules.— Hans Christian von Baeyer
b : the mathematical ratio of the tangential frictional force per unit area to the velocity gradient perpendicular to the direction of flow of a liquid

called also coefficient of viscosity

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Examples of viscosity in a Sentence

conducted an experiment to determine the viscosity of motor oil

Recent Examples on the Web

Oil: Crude oil, a liquid composed mainly of carbon and hydrogen, is often black, but exists in a variety of colors and viscosities depending on its chemical composition. Christina Nunez, National Geographic, "Fossil fuels, explained," 2 Apr. 2019 For non-Newtonian fluids like oobleck, however, the viscosity changes in response to a shearing force. Jennifer Ouellette, Ars Technica, "New electrolyte recipe keeps lithium-ion batteries from catching fire," 23 Aug. 2018 Because watercolors have such low viscosity, the dynamics are very different—and thus, the techniques artists employ are also different. Jennifer Ouellette, Ars Technica, "Study: modern masters like Jackson Pollock were “intuitive physicists”," 26 Dec. 2018 Fluids with no viscosity at all, like superfluids, have some really weird properties. Chris Lee, Ars Technica, "Quark-gluon plasma reveals viscosity-free properties," 19 Dec. 2018 That said, coolant is important, because if your car starts running hot, then the oil has lower viscosity and doesn’t lubricate the engine as well. Popular Mechanics, "The Lightning-Fast Guide to Figuring Out What's Wrong With Your Car," 21 Nov. 2017 Secondly, the vehicle came with synthetic-blend motor oil with a 0W-20 viscosity rating. Ray Magliozzi,, "CAR TALK: Time To Trade Out Old Reliable For New Subaru?," 25 May 2018 The surface of the lava cools in both, but depending on its viscosity, the resulting rocks are very different. Maya Wei-haas, Smithsonian, "A Brief Glossary of Volcano Vocab," 25 May 2018 Volcanoes that form over land contain what's called silicic magma, which is high in silica and has a high viscosity. Sarah Gibbens, National Geographic, "No, Hawaii's Volcano Won't Trigger a Mega-Tsunami," 17 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'viscosity.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of viscosity

14th century, in the meaning defined at sense 1

History and Etymology for viscosity

Middle English viscosite, from Anglo-French viscosité, from Medieval Latin viscositat-, viscositas, from Late Latin viscosus viscous

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Statistics for viscosity

Last Updated

25 Jun 2019

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Time Traveler for viscosity

The first known use of viscosity was in the 14th century

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vis·​cos·​i·​ty | \ vis-ˈkäs-ət-ē How to pronounce viscosity (audio) \
plural viscosities

Medical Definition of viscosity

1 : the quality of being viscous especially : the property of resistance to flow in a fluid or semifluid
2 : the ratio of the tangential frictional force per unit area to the velocity gradient perpendicular to the direction of flow of a liquid

called also coefficient of viscosity

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Comments on viscosity

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to take the place or position of

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