Glossary
What is Bitcoin?
In one sentence
Bitcoin is the first and largest cryptocurrency — a digital money with a fixed maximum supply and no company or government controlling it.
Bitcoin launched in 2009 and is the original cryptocurrency. Its proposition is deliberately narrow: a form of money that no single party can create more of, freeze, or reverse. Every other cryptocurrency exists in some sense as a response to it.
Two design choices define it. The first is a hard supply cap: there will only ever be 21 million bitcoin, released on a schedule that halves roughly every four years. The second is proof-of-work mining, which is how new bitcoin enter circulation and how the network agrees on transaction history without a central authority.
Bitcoin does considerably less than newer blockchains. It has no meaningful smart contract capability, processes a limited number of transactions per second, and changes very slowly. Supporters treat that conservatism as the point — a monetary network is not a place you want rapid experimentation. Critics point to the energy consumption of mining and the limited throughput.
It is often described as “digital gold”. That is a narrative about what it might become rather than a settled description of how it behaves; bitcoin has historically been far more volatile than gold and has often fallen alongside risk assets rather than acting as a safe haven.
For example
One bitcoin can be divided into 100 million units called satoshis, so you never need to buy a whole one.