/ Dictionary / Index Q quinternion: Meaning and Definition of Find definitions for: quin•ter•ni•on Pronunciation: (kwin-tûr'nē-un), [key] — n. Bookbinding. five gathered sheets folded in two for binding together. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. quintefoil Quintero Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language