> So when is a currency a currency? What is the difference between an apple and a pound note? (Assume the apple never decays) There's no difference. Currencie

> So when is a currency a currency? What is the difference between an apple and a pound note? (Assume the apple never decays) There's no difference. Currencies are just goods whose primary use is as a means of exchange. The usually enumerated properties of a currency are (1) a means of exchange, (2) a store of value, and (3) a unit of account. (2) is really not required; almost all modern and historical currencies fail it to some degree. (1) is the true test, and it amounts simply to being able to find someone willing to exchange what you want for some amount of your would-be currency; (3) follows from (1), since (1) implies agreeing a price in units of your currency.