Synonyms for Custom (same or very similar meaning)
WordNet sense 1 (money collected under a tariff):
customs, impost, customs dutyWordNet sense 2 (a specific practice of long standing):
traditionWordNet sense 3 (made according to the specifications of an individual):
custom-made, customised, customized, custom-madeWordNet sense 4 (accepted or habitual practice):
usage, usanceFrom the ODE community, based on WordNetadd/edit