/ Dictionary / Index S sponsion: Meaning and Definition of Find definitions for: spon•sion Pronunciation: (spon'shun), [key] — n. an engagement or promise, esp. one made on behalf of another. an engagement made on behalf of a government by an agent acting beyond his or her authority or without the required authorization and not binding on the government unless ratified. the act of becoming surety for another. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. spongy parenchyma sponson Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language