The paper forms part of the book compiling papers presented at the MaiSymposium at WU in 2020. The paper discusses the meaning and scope of various terms in Article 2(1) and 2(2) of OECD MC, 2017 with a focus on taxes on income. The paper undertakes a historical analysis of various deliberations that led to the framing of Article 2(1) and 2(2) to answer key questions such as why are few taxes specifically deemed as taxes on income and on capital, what is the significance of payroll taxes, should income be understood autonomously. The article also highlights the changing trend relating to Article 2(1) and 2(2) as many countries are increasingly including these paras in their treaties unlike their earlier treaty practice.