Define national income.

National income is the total value of all goods and services produced within a country's borders over a specific period of time, usually a year. It includes income earned by individuals, businesses, and the government, and is used as a measure of a country's economic performance and standard of living.

National income refers to the total monetary value of all finished goods and services produced in a country during a specified period of time, usually one year. It measures the overall economic output of a nation and serves as an indicator of its economic performance and well-being. National income is often expressed as a total value or as a per capita value to provide a more accurate comparison between countries of different sizes.