The Collaborative International Dictionary of English v.0.48:
Consuetude \Con"sue*tude\ (?; 144), n. [L. consuetudo. See Custom.] Custom, habit; usage. [R.] [1913 Webster] To observe this consuetude or law. --Barnes . [1913 Webster]WordNet (r) 3.0 (2006):
consuetude n 1: a custom or usage that has acquired the force of law