viscosity index
noun
: an arbitrary number assigned as a measure of the constancy of the viscosity of a lubricating oil with change of temperature with higher numbers indicating viscosities that change little with temperature
Examples of viscosity index in a Sentence
Recent Examples on the Web
An oil’s resistance to thinning in hotter temperatures is called the viscosity index.
—
Paul Weissler, Popular Mechanics, 31 Aug. 2020
Resistance to thinning with increasing temperature is called viscosity index.
—Paul Weissler, Popular Mechanics, 14 Feb. 2019
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Paul Weissler, Popular Mechanics, 31 Aug. 2020
Resistance to thinning with increasing temperature is called viscosity index.
—Paul Weissler, Popular Mechanics, 14 Feb. 2019
Cite this Entry
“Viscosity index.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/viscosity%20index. Accessed 22 May. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share