ultima ratio regum

[ oo l-ti-mah rah-tee-oh rey-goo m; English uhl-tuh-muh rey-shee-oh ree-guh m ]
/ ˈʊl tɪˌmɑ ˈrɑ tiˌoʊ ˈreɪ gʊm; English ˈʌl tə mə ˈreɪ ʃiˌoʊ ˈri gəm /

Latin.

the final argument of kings (a resort to arms): motto engraved on the cannon of Louis XIV.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019