Bitcoin is the first and most widely recognized cryptocurrency. It enables peer-to-peer exchange of value in the digital realm through the use of a decentralized protocol, cryptography, and a mechanism to achieve global consensus on the state of a periodically updated public transaction ledger called a 'blockchain.'
Practically speaking, Bitcoin is a form of digital money that (1) exists independently of any government, state, or financial institution, (2) can be transferred globally without the need for a centralized intermediary, and (3) has a known monetary policy that arguably cannot be altered.
At a deeper level, Bitcoin can be described as a political, philosophical, and economic system. This is thanks to the combination of the technical features it integrates, the wide array of participants and stakeholders it involves, and the process for making changes to the protocol.
Bitcoin can refer to the Bitcoin software protocol as well as to the monetary unit, which goes by the ticker symbol BTC.
Launched anonymously in January 2009 to a niche group of technologists, Bitcoin is now a globally traded financial asset with daily settled volume measured in the tens of billions of dollars. Although its regulatory status varies by region and continues to evolve, Bitcoin is most commonly regulated as either a currency or a commodity, and is legal to use (with varying levels of restrictions) in all major economies. In June 2021, El Salvador became the first country to mandate Bitcoin as legal tender.