This Article provides comprehensive definitions for key terms used throughout the Decree-Law to ensure precise interpretation of the Value Added Tax regime. It defines core concepts such as 'Taxable Supply', 'Exempt Supply', 'Deemed Supply', 'Input Tax', and 'Output Tax'. It clarifies the meanings of 'State', 'Authority', 'Capital Assets', and 'Related Parties'. The Article also includes definitions for 'Electronic Invoicing System', 'Electronic Invoice', and 'Electronic Credit Note', reflecting modern compliance mechanisms. These definitions apply unless the context requires otherwise, serving as the interpretative dictionary for the entire VAT legislation.