con·sue·tude /ˈkɑn(t)swɪˌtud, kənˈsuə, ˌtjud/ 習俗,慣例
Con·sue·tude n. Custom, habit; usage. [R.] To observe this consuetude or law. --Barnes. ◄ ►
consuetude n : a custom or usage that has acquired the force of law