MONEY - Portable pieces of stamped paper or metal in use of a medium of exchange.

It can be any good or token that fulfills its functions as a medium of exchange, store of value, and unit of account.

There are also less tangible forms of money:

Checks, debit cards and wire transfers are used as means to more easily transfer larger amounts of money between bank accounts.

Electronic money is an entirely non-physical currency that is traded and used over the internet.

Credit is often loosely referred to as money. However, to be strictly accurate credit is a money substitute and not money proper.