BTC, or Bitcoin, is the world's first decentralized digital currency, created in 2009 by an anonymous entity known as Satoshi Nakamoto. It operates on a technology called blockchain, a public, distributed ledger that records all transactions securely.

Unlike traditional currencies, Bitcoin has no central authority like a bank or government. Transactions are verified by a network of computers through a process called "mining," and new bitcoins are created as a reward for this work. Its scarcity (capped at 21 million units) and decentralized nature are key to its value, making it a popular investment and a medium for peer-to-peer online payments.