ultima ratio regum*: Meaning and Definition of

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.
  1. 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.