/ Dictionary / Index U United Nations Day: Meaning and Definition of Find definitions for: Unit'ed Na'tions Day" Pronunciation: [key] the anniversary of the United Nations on October 24, marking its founding in 1945. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. United Nations Children's Fund United Nations Educational, Scientific, and Cultural Organization Related Content Daily Word Quiz: prevalent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language