viscosity index

noun

Definition of viscosity index

: 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

Recent Examples of viscosity index from the Web

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

First Known Use of viscosity index

1929


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