1. a digital currency created and held electronically, operating without a central bank and using cryptography to verify transactions
Usage: often capitalized when referring to the system or network; informal: often abbreviated as BTC
2. a single unit of this digital currency
Usage: countable; can be subdivided into smaller units called satoshis

Examples

• Bitcoin was created in 2009 as a peer-to-peer electronic cash system.
• She invested in bitcoin as part of her cryptocurrency portfolio.
• The price of bitcoin fluctuates significantly based on market demand.
• Many online retailers now accept bitcoin as a form of payment.
• He owns several bitcoins stored in a digital wallet.
• Bitcoin transactions are recorded on a public ledger called the blockchain.