Reference
The words, unhooked from hype.
A short lexicon for the primer. Same ideas as the lessons, in lookup form.
- Address
- A public identifier for an account, written as 0x plus 40 hex characters. Anyone can send assets to it. Only the matching private key can move them out.
- Block
- A batch of transactions plus a fingerprint of the previous block. New Ethereum blocks arrive about every 12 seconds.
- Blockchain
- A public ledger made of blocks chained together. Changing old data breaks every later fingerprint, which the rest of the network would reject.
- dApp
- A “decentralized app”: a website or client that talks to smart contracts instead of (or as well as) a company's server.
- ETH / ether
- Ethereum's native currency. Used to transfer value and to pay gas. 1 ETH = 10^18 wei.
- Explorer
- A searchable website (Etherscan is the well-known one) that shows blocks, transactions, and contract data already on the public chain.
- Gas
- The unit of work a transaction takes. You pay for gas in ETH. Congestion raises the price; a failed transaction can still charge you.
- Layer 2
- A network that handles transactions more cheaply, then posts a summary back to Ethereum. Same keys, usually lower fees.
- Mempool
- The waiting room of broadcast transactions that have been signed but not yet included in a block.
- Nonce
- A per-account counter on transactions. It stops the same signed payment from being replayed.
- Private key
- A secret number that can sign transactions for an address. The wallet keeps it. Anyone who copies it can spend the funds.
- Proof of stake
- Ethereum's method of agreeing on the next block. Validators lock ETH as collateral and can lose some of it if they cheat or vanish.
- Seed phrase
- 12 or 24 words that can rebuild your keys. Treat them like the key to a safe. No legitimate support agent will ask for them.
- Smart contract
- A program stored on Ethereum at its own address. It holds assets and runs exactly as written when someone calls it.
- Token
- A balance tracked by a smart contract, not by Ethereum itself. Stablecoins and NFTs are tokens. You still need ETH to pay gas.
- Transaction
- A signed instruction from an address: send ETH, call a contract, or deploy one. It is pending until a block includes it.
- Validator
- Software — and the staked ETH behind it — that proposes and attests to blocks under proof of stake. Solo validators post 32 ETH.
- Wallet
- Software or hardware that stores keys and helps you sign. It is not a bank account; the ledger is the source of balances.
- Wei
- The smallest unit of ETH. Wallets show ETH; the protocol counts wei.