/ Dictionary / Index C closed union: Meaning and Definition of Find definitions for: closed' un'ion Pronunciation: [key] a labor union in which admission of new members is restricted by rigid requirements. Cf. open union. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. closed traverse closed universe Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language