First published 11 February 2020 as a long A-to-Z dump. We rewrote it in August 2026 into the dozen terms that actually stop people. If a word is not here, you probably do not need it yet. For the six-step path, start at Learn.
Wallet
Software or hardware that holds keys, or a company account labelled “wallet”. The network holds the coins. Only keys (or the company’s promise) can move them. See how wallets actually work.
Seed phrase / recovery phrase
Usually 12 or 24 words that reconstruct the keys. Anyone who sees them can spend. Support will not ask for them. A screenshot is a backup for thieves. Write them once, store them offline, test a restore with a tiny amount.
Address
A public string you can share so someone can pay you. It is not secret. Sending to the right characters on the wrong network is still a loss. Copy, then check the first and last characters on the device screen.
Private key
The secret that can sign a spend. Seed phrases are a human-readable way to derive keys. If a site asks you to “import” or “validate” a phrase to claim something, it is not a wallet. It is a harvest.
Gas / network fee
Payment to whoever includes your transaction. On Ethereum it is called gas. Busy moments cost more. A failed transaction can still cost a fee. Cheap and fast is not the same as final and reversible.
Token
A balance inside a smart contract that your wallet knows how to display. ETH on Ethereum is native; USDT on Ethereum is a token. A pretty icon is not a certificate of authenticity. Copycat tickers exist.
Stablecoin
A token that aims to stay near a unit such as a US dollar. Some are company IOUs (you trust an issuer). Some are over-collateralised on-chain (you trust code, oracles, and liquidation). Pegs can break. “USD” in the name is branding.
Exchange
A company that matches buyers and sellers, or a pool of contracts that does something similar. Custodial exchanges can freeze accounts. Decentralised ones can still drain you via a bad approval. An order book is not a vault.
Market cap
Price multiplied by coins treated as circulating. A round number is a headline, not a law. Tiny unit prices on huge supplies are not discounts. Illiquid coins can print a market cap nobody could actually sell into.
On-chain / off-chain
On-chain means recorded on the public ledger. Off-chain means a company’s database, a receipt, or a promise. “I have bitcoin at an app” is often off-chain until you withdraw.
Confirmation
A transaction appearing in a block, then in the blocks that follow. Wallets show “sent” before the network has agreed. Exchanges wait for a number of confirmations because history can still reorganise for a moment.
Cold storage
Keys that are not sitting on an internet-connected daily driver. Still stealable if you photograph the backup. See the cold-storage guide.
This page is a map of language, not a product list and not financial advice. When a headline uses one of these words as a command, read it again as a description.
