What is Bitcoin?
A peer-to-peer settlement network and the fixed-supply digital asset it issues, operating without a company, an operator or an administrator.
Bitcoin is two things sharing a name: a network of independent computers that maintain a shared transaction ledger, and the unit of account that ledger tracks. Convention capitalises the network and lower-cases the coin.
What makes it unusual is not that it is digital, but that its rules are enforced by every participant rather than by an operator. Supply is fixed at 21 million by an issuance schedule that each node independently verifies; a block paying more than the schedule allows is simply rejected. There is no board that can revise it, no support line that can reverse a transaction, and no jurisdiction that can switch it off.
Related terms
Blockchain
The append-only chain of blocks that records every Bitcoin transaction, where each block commits to the one…
How it worksProof of work
The mechanism that secures Bitcoin: miners must find a hash below a difficulty target, which is expensive to…
BasicsSatoshi (sat)
The smallest unit of bitcoin: one hundred-millionth of a BTC. There are 100,000,000 satoshis in one bitcoin.
EconomicsHalving
The scheduled 50% reduction of the block subsidy, occurring every 210,000 blocks — roughly every four years.
This definition is part of the Bitcoin Logical glossary. For the fuller explanation, start with Learn, or see the live numbers on The Bitcoin Signal.