Bitcoin and crypto glossary

Plain definitions of the words that keep coming up. Each one is written to make sense on its own.

Bitcoin Church South AfricaBi…Jiří Karafiát
Bitcoin
A digital currency that runs on a public network with no company or government in charge. New coins are issued on a fixed schedule and the supply is capped at 21 million.
Blockchain
The shared public ledger that records every Bitcoin transaction. Anyone can read it, and no single party can quietly rewrite it.
Satoshi
The smallest unit of Bitcoin: one hundred-millionth of a coin. You never have to buy a whole bitcoin.
Wallet
Software or a device that stores the keys controlling your coins. The coins live on the network; the wallet holds the proof that they are yours.
Seed phrase
A list of 12 or 24 words that can restore your entire wallet. Anyone who reads it can take your coins, and nobody legitimate will ever ask for it.
Private key
The secret number that authorises spending from an address. Whoever holds it controls the funds, which is why self-custody is a real responsibility.
Self-custody
Holding your own keys instead of leaving coins with an exchange. It removes the risk of the platform failing and adds the risk of you losing the keys.
Cold storage
Keeping keys on a device that never touches the internet, usually a hardware wallet. It is the standard answer to remote theft.
Exchange
A company that converts money into crypto and back. Your coins sit in its accounts until you withdraw them to your own wallet.
KYC
Identity checks an exchange must run before it lets you trade. Expect an ID document and sometimes proof of address.
P2P trading
Buying directly from another person, with the platform only holding the coins in escrow. Common where banks will not serve crypto companies.
DCA
Buying a fixed amount on a fixed schedule instead of trying to time the market. It does not guarantee a profit; it removes the timing decision.
Spread
The gap between the buy price and the sell price. It is a real cost even when a service advertises zero commission.
Volatility
How sharply the price moves. Bitcoin can move double digits in a day, in either direction, which is why position size matters more than prediction.
Halving
The roughly four-yearly event that cuts the rate of new coin issuance in half. It is written into the rules, not decided by anyone.
Mining
The process of securing the network with computing power in exchange for newly issued coins and fees.
Node
A computer that keeps a full copy of the ledger and checks every rule for itself. Running one means trusting nobody else's version of events.
Lightning Network
A layer built on top of Bitcoin for small, instant, cheap payments, settling back to the main chain later.
Stablecoin
A token designed to hold a steady value, usually one US dollar. It depends on whoever issues it actually holding the reserves.
CFD
A leveraged bet on price that never gives you any coins. The large majority of retail accounts lose money trading them.

Definitions are educational. Rules and products change; check a current official source before acting on any of this.