/ Dictionary / Index O open universe: Meaning and Definition of Find definitions for: o'pen u'niverse Pronunciation: [key] — Astron. Astron. a model of the universe in which the universe expands forever because there is not enough mass to counteract the expansion by means of gravitational attraction. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. open union open university Related Content Daily Word Quiz: diligent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language