Source : Webster's Revised Unabridged Dictionary (1913)

Consuetude \Con"sue*tude\ (?; 144), n. [L. consuetudo. See
   {Custom}.]
   Custom, habit; usage. [R.]

         To observe this consuetude or law.       --Barnes
         .

Source : WordNet®

consuetude
     n : a custom or usage that has acquired the force of law