to correct the OP

currency is anything used as a medium of exchange

MONEY is a specific currency used by a community/nation and ratified as the official currency of that society.. money in history has been controlled by the rulers of that society and distributed/taxed and accounted by those rulers

we in the bitcoin community/society deem bitcoin as our money
much like europeans claim euro as their money, much like americans claim dollar as their money

but europeans do not claim dollars as their money. but still recognise dollar as a medium of exchange foreign currency vs euro