Tax treaty definitions clarify residency, taxable persons, enterprises, national status and competent authority roles under the DTAA. Defines key terms for the India-Bhutan tax treaty: territorial scope of each State; 'person', 'company' and 'enterprise' as taxable units; 'enterprise of a Contracting State' by residence; 'international traffic' tied to place of effective management; the competent authority in each State; 'national' for individuals and legal persons; 'tax' limited to Indian or Bhutanese taxes excluding penalties; and fiscal/income year definitions for India and Bhutan, with undefined terms adopting domestic tax-law meanings.