Tax treaty definitions set territorial scope, resident enterprises, nationals, international traffic and competent authority roles. Article 3 fixes core definitions for the Japan-India Convention: territorial scope of each State including maritime zones; 'person', 'company', and 'enterprise of a Contracting State'; the definition of 'nationals' for each State; 'international traffic' limited to ships or aircraft operated by an enterprise of a Contracting State (except solely between places in the other State); designation of each State's competent authority; and a rule that terms not defined in the Convention carry the meaning given by the applying Contracting State's domestic tax law unless the context requires otherwise.