Once it is understood that money is a belief system at its core, one can begin to think about the different functions of money. Again, to understand what Bitcoin is, it is important to understand what money is beyond simply a system of belief. The first part of my answer to what money is was fundamentally philosophical. This second part is mostly rooted in economics. Well-regarded economists have come up with three functions of money that I am merely passing along to you and describing in my own words. These three functions of money are as (1.) a store of value, (2.) a medium of exchange, and (3.) a unit of account.