/ Dictionary / Index U ultima ratio regum*: Meaning and Definition of Find definitions for: ul•ti•ma ra•ti•o re•gum Pronunciation: (ool'ti-mä" rä'tē-ō" rā'goom Eng. ul't&schwa-m&schwa rā'shē-ō" rē'g&schwam), [key] — Latin. Latin. the final argument of kings (a resort to arms): motto engraved on the cannon of Louis XIV. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ultimacy ultimate Related Content Daily Word Quiz: diaphanous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language