viscosity

noun

vis·​cos·​i·​ty vi-ˈskä-sə-tē 

plural viscosities

1

: the quality or state of being viscous : a sticky or glutinous consistency

2

a

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

Synonyms

• consistence
• consistency
• density
• thickness
• viscidity

Examples of viscosity in a Sentence

conducted an experiment to determine the viscosity of motor oil

Recent Examples on the Web

Researchers utilized a special collagen gel for adhesion, which was challenging due to its natural viscosity. —Jijo Malayil, Interesting Engineering, 25 June 2024

The combination of the slow wind speeds on Titan—a product of the moon’s thick nitrogen atmosphere—and the density and viscosity of methane and ethane mean that the average wave height would only be a few inches. —Tom Hawking, Popular Science, 20 June 2024

This fluid’s compressibility, viscosity and transparency are all programmable. —Simon Makin, Scientific American, 19 June 2024

The fluid has 1/8th the electrical conductivity of air and is roughly the viscosity of cooking oil, Martinez says. —Charles Q. Choi, IEEE Spectrum, 13 June 2024

Word History

Etymology

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

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing viscosity

• coefficient of viscosity
• viscosity index

Kids Definition

viscosity

noun

vis·​cos·​i·​ty vis-ˈkäs-ət-ē 

plural viscosities

: the quality or state of being viscous

especially : the characteristic of a fluid that resists flow

an oil of high viscosity

Medical Definition

viscosity

noun

vis·​cos·​i·​ty vis-ˈkäs-ət-ē 

plural viscosities

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