The Definition of Money

There is a long history of disagreements on the definition of money ([15] chaps. 2, 3; [36]). Two aspects of the problem must be distinguished. First, precisely what qualities must a thing have in order to be called money? This question about the concept of money has centred on the qualities of being a means of payment, a store of value and a unit of account. Second, what in fact are the particular things at any time to which the concept of money refers? This question concerns the empirical content of the concept of money. It is a particularly pressing problem when the quantity of money has to be measured for econometric work.