This is commonly described as a digital currency that is non-government. Some people call it cyber currency or crypto currency. It is basically a description of a currency as its value is mainly in the description. One has to learn how to bitcoin mine in order to make money with it.
Bitcoin is a peer payment system that was created as an open source software in 2009. It was developed by Satoshi Nakamoto to be used as a cryptocurrency. It is called a cryptocurrency because it uses cryptography to create and transfer money. Users of the system can send payments to vendors or merchants by broadcasting digital messages across the network. If this system interests you, you may want to learn more about What is Bitcoin.