Bitcoin
noun
Bit·coin ˈbit-ˌkȯin 
variants or less commonly bitcoin
: a digital currency created for use in peer-to-peer online transactions
Introduced in 2008 by a person or group using the name Satoshi Nakamoto, Bitcoin is the most prominent of a group of virtual currencies—money that exists mainly as computer code—that have no central issuing authority.
Carter Dougherty
Carter Dougherty… Bitcoin … is backed by no government and has a fluctuating value linked in part to a scarcity that is mathematically predetermined. Glenn Zorpette
Glenn ZorpetteThe venture capital industry is beginning to take a good, hard look at a new financial instrument coming out of the bitcoin community—Initial Coin Offerings, or ICOs. Richard Kastelein
Richard Kastelein also usually bitcoin : a unit of this currency
Commercial space venture Virgin Galactic—which announced on Nov. 22 that it would start accepting bitcoins to reserve a refundable $250,000 seat on a future trip—is just the latest of many businesses that have recently embraced the decentralized virtual payment system. (At press time, 1 bitcoin was worth roughly $879.) Time
Time 
Example Sentences
Recent Examples on the Web The desk struck a relationship with Poloniex, its Boston neighbor, after Poloniex became one of the earliest exchanges to list Ether, the native coin of Ethereum, the biggest cryptocurrency network next to Bitcoin. Robert Hackett, Fortune, 26 Feb. 2018 Bitcoin, however, has become the cryptocurrency standard operating much like U.S. dollar would operate in public currency markets, but in the crypto realm. Michael C. Dealoia, cleveland.com, 25 Feb. 2018 The town decided early on to attract crypto-entrepreneurs, for example by allowing companies to incorporate based on bitcoin wealth, rather than insisting that it be converted into fiat currency. The Economist, 24 Feb. 2018
Robert Hackett, Fortune, 26 Feb. 2018 Bitcoin, however, has become the cryptocurrency standard operating much like U.S. dollar would operate in public currency markets, but in the crypto realm. Michael C. Dealoia, cleveland.com, 25 Feb. 2018 The town decided early on to attract crypto-entrepreneurs, for example by allowing companies to incorporate based on bitcoin wealth, rather than insisting that it be converted into fiat currency. The Economist, 24 Feb. 2018 Word History
Etymology
bit entry 4 + coin entry 1
First Known Use
2008, in the meaning defined above