Source : Webster's Revised Unabridged Dictionary (1913)

Quo warranto \Quo" war*ran"to\ [So called from the Law L. words
   quo warranto (by what authority), in the original Latin form
   of the writ. See {Which}, and {Warrant}.] (Law)
   A writ brought before a proper tribunal, to inquire by what
   warrant a person or a corporation acts, or exercises certain
   powers. --Blackstone.

   Note: An information in the nature of a quo warranto is now
         common as a substitute for the writ. --Wharton.

Source : WordNet®

quo warranto
     n : a hearing to determine by what authority someone has an
         office or franchise or liberty