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 Kim continued to explain that sauce must not be characterized by its viscosity or texture. Michelle Santiago Cortés,, "What’s The Difference Between A Dip, A Sauce, & A Condiment? A Very Serious Investigation," 22 Apr. 2021 As the temperature dropped, the worms could alter the viscosity or thickness of the liquid, turning the liquid into an oozy blob of sorts, just like what happens with plastics and other chemical polymers when they are cooled. Eric Niiler, Wired, "Researchers Are Studying These Worm Blobs to Build Robots," 17 Feb. 2021 In a real volcano, this sudden increase in the magma's viscosity would trap bubbles of escaping gas. Harini Barath, Scientific American, "‘Nanolites’ Can Trigger Dangerous Volcanic Explosions," 4 Jan. 2021 Another study in the Journal of the International Society of Sports Nutrition has suggested that alkaline water may affect blood viscosity. Bruce Y. Lee, Forbes, "FDA: Did This Alkaline Water Brand Cause 5 Cases Of Liver Failure?," 19 Mar. 2021 Gel hand sanitizer is also made by adding a powder called a carbomer, often made with benzene, to create viscosity, the pharmacy said. Anna Edney,, "Some hand sanitizers used to fight COVID-19 found to be tainted with cancer-causing chemical," 24 Mar. 2021 In seminal work published in 1969, Keith Moffatt, then a young Cambridge University lecturer, proved that the measure of the total knottedness and linkage in ideal fluids—ones, like liquid helium, that lack viscosity—stays constant over time. Natalie Wolchover, Scientific American, "Mysteries of Fluid Flow Unraveled by Knots," 11 Dec. 2013 Lopez had been on blood thinners, but the coronavirus increases the viscosity of the blood. Thomas Curwen, Los Angeles Times, "She was dying of COVID-19. Her last hope would save her or kill her," 12 Mar. 2021 The reason has to do with the wettability of the container and the viscosity of the substance. H. Joachim Schlichting, Scientific American, "Ketchup Is Not Just a Condiment: It Is Also a Non-Newtonian Fluid," 12 Mar. 2021

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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Time Traveler for viscosity

Time Traveler

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

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Statistics for viscosity

Last Updated

2 May 2021

Cite this Entry

“Viscosity.” Dictionary, Merriam-Webster, Accessed 7 May. 2021.

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More Definitions for viscosity


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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