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

Vehicles that pass inspection will receive a higher viscosity oil, which also requires a new oil fill cap, an oil filter replacement, and an owner's manual insert. —Tahar Rajab, MSNBC Newsweek, 1 May 2025

Vehicles that pass inspections will receive a new oil fill cap, higher viscosity oil, oil filter replacement and an update to their owner's manual, also free of charge. —Mary Walrath-Holdridge, USA Today, 30 Apr. 2025

When in a supercritical state, water has lower viscosity than liquid water, yet higher than steam, allowing for improved flow dynamics in turbines and heat exchangers. —David Szondy, New Atlas, 13 Mar. 2025

Dishes that have food with a high viscosity, like honey or curry, will need to soak for longer, whereas items with lower viscosity foods, such as coffee or soup, can soak for less time. —Claire Hoppe, Better Homes & Gardens, 26 Sep. 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

Rhymes for viscosity

• atrocity
• ferocity
• monstrosity
• pomposity
• porosity
• precocity
• schistosity
• velocity
• verbosity
• animosity
• curiosity
• generosity

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