Even so, the latter notion is probably more widely held than the former. A part of the popular misunderstanding about money is the belief that money is the tangible form which it sometimes takes - notes and coins. Money is in fact wholly conceptual and definable only as a widely accepted medium of exchange. At different times people have chosen to use different items as money, such as seashells and cigarettes, while metal coins have sometimes ceased to be money. What remains the same, whatever the form it takes, is that money is a medium of exchange.
Most people think of money as something administered by the government.
It is true that government has assumed control over the issuance of currency, and has usually forbade the use of other currencies, through the use of legal tender laws. It is people in their transactions accepting a certain good as a medium of exchange that allows money to exist. If that acceptance is withdrawn then money ceases to be, whatever exhortation the government may use. There are cases of people rejecting the government's decreed currency. In Israel, for example, when inflation raged in the 1970s, people chose to recognise dollars as money and used them instead of the official tender.