Breadcrumb Home > Dictionary > Index V viscosity index: Meaning and Definition of Find definitions for: viscos'ity in"dex Pronunciation: [key] — Auto., Mach. Auto.,Mach. an arbitrary scale for lubricating oils that indicates the extent of variation in viscosity with variation of temperature. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. viscosity viscount TrendingHere are the facts and trivia that people are buzzing about. Hanukkah Origins of the Christmas Holiday Jewish Holidays, 2010-2030 (A.M. 5770-5791) Western Christian Holidays, 2010-2030 Krampus: The Christmas Devil Kwanzaa ✖ Related Content Daily Word Quiz: praedial Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language