Qué es custom? Qué es custom? A practice followed by people of a particular group or region.A habitual practice of a person: my custom of reading a little before sleep. See Synonyms at habit.Law A common tradition or usage so long established that it has the force or validity of law. Habitual patronage, as of a store.Habitual customers; patrons.Duties or taxes imposed on imported and, less commonly, exported goods.The governmental agency authorized to collect these duties.The procedure for inspecting goods and baggage entering a country.Tribute, service, or rent paid by a feudal tenant to a lord.Made to order.Specializing in the making or selling of made-to-order goods: a custom tailor.