/ Dictionary / Index U unionize: Meaning and Definition of Find definitions for: un•ion•ize Pronunciation: (yn'yu-nīz"), [key] — v., -ized, -iz•ing. —v.t. to form into a union. to organize into a labor union; bring into or incorporate in a labor union. to subject to the rules of a labor union. —v.i. to form a union. to join in a labor union. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: unionize (Thesaurus) unionist union jack Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language