Tax treaty definitions establish operative meanings and require undefined terms to default to domestic tax law meanings. Article 4 defines key terms for the India-Macao DTAA including territorial scope, Contracting Party, competent authority, person, company, publicly traded company, principal class of shares, recognised stock exchange, collective investment fund or scheme, tax, requesting/ requested Party, information gathering measures, and information. It provides that undefined terms shall have the meaning under the law of the applying Contracting Party, with meanings under that Party's tax laws prevailing, and allows the competent authorities to agree a common meaning under Article 12.