/ Dictionary / Index Q quincentennial: Meaning and Definition of Find definitions for: quin•cen•ten•ni•al Pronunciation: (kwin"sen-ten'ē-ul), [key] — adj. pertaining to or marking a period of 500 years. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: quincentennial (Thesaurus) quincentenary quincuncial Related Content Daily Word Quiz: cur Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language