The meaning ofTAXis a charge usually of money imposed by authority on persons or property for public purposes. How to usetaxin a sentence. From incometaxto sales and propertytax, it’s important to understand keytaxdefinitions so you know what you owe and why you owe it. Learn more from the pros atH&R Block. TAXdefinition: 1. (an amount of) money paid to the government that is based on your income or the cost of goods or…. Learn more. Ataxis a mandatory financial charge or levy imposed on an individual or legal entity by a governmental organization to support government spending and public expenditures collectively or to regulate and reduce negative externalities. [1] .