With the Bitcoin price so volatile everyone is curious. Bitcoin, the category creator of blockchain technology, is the World Wide Ledger yet extremely complicated and no one definition fully encapsulates it. By analogy it is like being able to send a gold coin via email. It is a consensus network that enables a new payment system and a completely digital money.
It is the first decentralized peer-to-peer payment network that is powered by its users with no central authority or middlemen. Bitcoin was the first practical implementation and is currently the most prominent triple entry bookkeeping system in existence.
Beware of the confusingly similar Bcash, BCH, Bitcoin Cash project.