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.