Breadcrumb Home > Dictionary > Index I isodef: Meaning and Definition of Find definitions for: i•so•def Pronunciation: (ī'su-def"), [key] — n. uniform deficiency, esp. a line connecting points of equal deviation from a mean, as on a chart or graph. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. isocyclic isodiametric ✖ Related Content Daily Word Quiz: hortatory Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language