What is the difference between income and income tax

Income is the amount of money earned by the economic agents (households, firms and public sector) in exchange for offering in the markets the factors of production that they own (land, labor, capital and entrepeneurship).

Income tax is the amount, usually measured as a percentage of income, that those agents which are income earners have to pay to the public sector, to generate public revenues that will be used to provide public services for all citizens.