Bitcoin is a cryptocurrency and currently one of the most well-known and valuable cryptocurrencies globally. It features:

1. **Decentralization**: Bitcoin operates without a central authority; all transactions are recorded on a blockchain maintained and verified by a global network of nodes.

2. **Blockchain Technology**: Transactions in Bitcoin rely on blockchain technology, a decentralized distributed ledger that records all transaction history.

3. **Anonymity and Transparency**: Bitcoin transactions are relatively anonymous, displaying addresses rather than personal information, yet transaction data is publicly visible, ensuring transparency.

4. **Fixed Supply**: Bitcoin has a fixed total supply, expected to not exceed 21 million coins, unlike traditional currencies susceptible to devaluation due to monetary policy.

5. **Investment and Volatility**: Bitcoin prices are highly volatile, attracting investor attention but also posing investment risks.