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. Jewish Holidays, 2010-2030 (A.M. 5770-5791) Western Christian Holidays, 2010-2030 12 Steps to a New Year New Year's Resolution to Slim Down? Martin Luther King Speeches Books of the Bible: Old Testament Books in Order ✖ Related Content Daily Word Quiz: antediluvian Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language