The rails themselves: what the ledger is and who keeps it honest.
BlockchainFoundation
A shared digital ledger maintained across many computers. Records are grouped into blocks and linked in order, making past entries very hard to change.
Works with Block · Node · Public Ledger
BlockFoundation
A batch of transactions recorded together on a blockchain, time-stamped and linked to the block before it.
Works with Blockchain
NodeFoundation
A computer running blockchain software that keeps a copy of the ledger and helps check and relay transactions.
Works with Blockchain
MainnetFoundation
The live, real-value version of a blockchain where actual transactions take place.
Works with Blockchain
TestnetFoundation
A practice version of a blockchain using valueless test tokens, used to try things out without risking real funds.
Works with Blockchain
Layer 1Operator
A base blockchain that settles its own transactions, such as the main networks themselves.
Works with Blockchain
Layer 2Operator
A network built on top of a Layer 1 to process transactions faster or cheaper, then record results back to the base layer.
Works with Rollup · Layer 1 · Gas Fee
SidechainAdvanced
A separate blockchain connected to a main chain that runs under its own rules while allowing assets to move between them.
Works with Blockchain
BridgeOperator
A tool that moves assets or information from one blockchain to another. Bridges add steps and have been a frequent target of technical problems.
Works with Wrapped Token · Wrong Chain Error · Network Selection · Blockchain
ConsensusAdvanced
The process by which a network agrees on which transactions are valid and what the shared record says.
Proof of WorkAdvanced
A consensus method where computers compete to solve a calculation to add the next block, consuming energy in the process.
Works with Consensus · Block
Proof of StakeAdvanced
A consensus method where participants lock up tokens for the chance to validate blocks, generally using far less energy than proof of work.
Works with Proof of Work · Consensus
ValidatorAdvanced
A participant that checks and confirms transactions under a proof-of-stake system.
MinerAdvanced
A participant that adds blocks under a proof-of-work system by performing the required calculations.
HashAdvanced
A fixed-length fingerprint produced from data. Any change to the data produces a completely different hash, which helps detect tampering.
Block ExplorerOperator
A public website for looking up transactions, addresses, and blocks on a given network.
RPCAdvanced
A connection point that lets wallets and apps read from and send transactions to a blockchain network.
Works with Blockchain
DecentralizationAdvanced
The degree to which control of a network is spread across many independent participants rather than held by one party.
Works with Spread
ForkAdvanced
A change to a network's rules. A soft fork is backward-compatible; a hard fork creates a separate path that older software will not follow.
RollupAdvanced
A Layer 2 design that processes many transactions off the main chain, then posts a compressed summary back to it. The main way busy networks scale today.
Works with Layer 2 · Layer 1
Chain IDAdvanced
A number that uniquely identifies a blockchain network. Wallets use it to make sure a transaction is signed for the intended network and not replayed on another.
Works with Transaction · Blockchain
FaucetOperator
A service that hands out small amounts of valueless testnet tokens so developers and learners can practice without real funds.
Works with Testnet
HalvingAdvanced
A scheduled event on some networks, most famously Bitcoin, where the reward for adding new blocks is cut in half — slowing how fast new coins are created.
Works with Miner · Proof of Work · Supply
Lightning NetworkAdvanced
A payment layer built on top of Bitcoin that routes many small, fast payments through channels, settling back to the main chain later.
GweiOperator
The small unit Ethereum gas prices are quoted in — one billionth of an ETH. When people say “gas is at 20,” they mean 20 gwei per unit of gas.
Works with Gas · Gas Fee · Priority Fee
Block HeightOperator
A block’s position number in the chain, counting from the very first block. Useful as a timestamp you can verify: “as of block N” is more precise than “as of Tuesday.”
Works with Block · Confirmation · Block Explorer
Cross-Chain SwapOperator
Exchanging an asset on one blockchain for an asset on another — via a bridge, a swap service, or an exchange. Every added chain hop adds fees, wait time, and a new place to make a wrong-network mistake.
Works with Bridge · Network Selection · Wrapped Token
Atomic SwapAdvanced
A cross-chain trade built so it either completes fully on both sides or cancels entirely — no half-finished state where one party holds everything.
Works with Cross-Chain Swap · Bridge · Smart Contract