A unit of account is a fundamental monetary unit used to measure value, making it possible to compare the values of various unrelated commodities.
Being a unit of account is a basic function of currency. The existence of a common unit of account shared by separate groups or individuals is useful for facilitating trade between them, as it provides a means of clearly measuring the relative value of the commodities being exchanged.
The most common units of account in the world today used for international transactions are the US Dollar and the Euro.
Money as a Unit of Account: Definition, Function & Example - Video & Lesson Transcript | Study.com
What is Unit Of Account? definition and meaning