Bitcoin (BTC) is the first and most well-known decentralized digital currency, created in 2009 by an anonymous person or group using the pseudonym Satoshi Nakamoto. It operates on a peer-to-peer network that allows users to send and receive payments without relying on a central bank, government, or third-party financial institution.

Bitcoin transactions are verified by network nodes through cryptography and recorded on a public distributed ledger called the blockchain. This transparent and immutable system ensures that all transactions are secure, traceable, and resistant to tampering.

The total supply of Bitcoin is capped at 21 million coins, making it a deflationary asset by design. It is often referred to as "digital gold" due to its scarcity and use as a store of value. Bitcoin is also used for online payments, cross-border transfers, and as a hedge against inflation in some economies.

As the pioneer of blockchain technology, Bitcoin laid the foundation for the broader cryptocurrency and decentralized finance (DeFi) ecosystems.