/ Dictionary / Index P postal union: Meaning and Definition of Find definitions for: post'al un"ion Pronunciation: [key] an international agreement on postal rates and services. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. postal storage car post-and-beam construction Related Content Daily Word Quiz: hale Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language