/ Dictionary / Index I ionopause: Meaning and Definition of Find definitions for: i•on•o•pause Pronunciation: (ī-on'u-pôz"), [key] — n. the transitional zone between the ionosphere and the mesosphere. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ionone ionophore Related Content Daily Word Quiz: entomology Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language