Breadcrumb Home > Dictionary > Index I Isa.: Meaning and Definition of Find definitions for: Isa. Pronunciation: [key] Isaiah. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. is Isaac ✖ Related Content Daily Word Quiz: donnybrook Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language