/ Dictionary / Index I IUS,: Meaning and Definition of Find definitions for: IUS Pronunciation: [key] — Rocketry. Rocketry. See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. -ium IV Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language