/ Dictionary / Index Z zwitterion: Meaning and Definition of Find definitions for: zwit•ter•i•on Pronunciation: (tsvit'ur-ī"un), [key] — n. Physical Chem. an ion with both a positive and a negative charge. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Zwinglian Zwolle Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language