Any given Currencies (e.g. U.S. Dollar, Euro, Japanese Yen, Chinese Yuan (Renminbi), British Pound Sterling) is a specific instantiation of Money.
Money is the overarching concept.
See what is money? and my answer to what is the relationship between money / currency and trust?
BitCoin is a type of money.
Money is a term used by economists for something that does three things (which I'll briefly explain in a moment):
BitCoin meets all three conditions -
You can acquire some and keep them, and they'll still be worth what they used to be (in the same way that a dollar is still worth a dollar, not that it'll still buy what a dollar used to.) That is to say, it's a store of value.
You can buy things with them. Not everyone will accept them, but you're probably going to have better luck finding someone to sell you a laptop for BitCoins than you are for Zim Dollars, despite the fact that Zimbabwe has a government.
You can price things in them, and they are fungible - that's to say that your BitCoin and my BitCoin are worth the same as each other. It's not like trying to trade in, say, oil paintings - people might accept a given Rembrandt for a given Picasso, but no-one would say "you can have my Turner seascape for (any) three Picassos." This makes them a unit of account.
What is Bitcoin ?
Bitcoin is a new currency that was created in 2009 by an unknown person using the alias Satoshi Nakamoto. Transactions are made with no middle men – meaning, no banks! Bitcoin can be used to book hotels on Expedia, shop for furniture on Overstock and buy Xbox games. But much of the hype is about getting rich by trading it. The price of bitcoin skyrocketed into the thousands in 2017.
What Is Money ?
Money is primarily a medium of exchange or means of exchange. It is a way for a person to trade what he has for what he wants. Ideal money has three critical characteristics: it acts as a medium of exchange; it is an economic good; and it is a means of economic calculation.
