Glossary

When a single entity controls most mining/validation power and can censor or reorganize blocks temporarily.

A shareable identifier derived from a public key (EOA) or contract. Use checksums; one wrong character sends funds to the wrong place.

A curated list of approved addresses that can mint, claim, or access a drop or contract feature.

A smart contract that lets users swap assets against a liquidity pool using a pricing formula instead of an order book.

Annualized return metrics: APR is simple interest; APY compounds. Protocols often quote APY; compare fee/reward sources and risk.

A batch of transactions plus metadata (number, timestamp, parent hash, transaction/Merkle root, producer). Blocks link via hashes.

A public website to view blocks, transactions, addresses, logs, and contract metadata independently of your wallet UI.

What a miner/validator earns for proposing a valid block: the subsidy (if any) plus transaction fees. Subsidies often decline over time (e.g., halvings).

A system that moves value/data between chains or rollups. Usually a lock-and-mint or burn-and-mint pattern; carries smart contract and operator risk.

The property of a system to keep working even if some participants are malicious or faulty, up to a defined threshold.

A numeric identifier for a blockchain network (e.g., Ethereum mainnet 1, Sepolia 11155111). Prevents cross-chain replay.

Tokens actually in the market—excluding locked, burned, or lost coins. Used with price to compute market cap.

A wallet where private keys stay offline (hardware device or air-gapped). Safer for savings; less convenient for daily use.

Each block added on top of your transaction increases its confirmations, making it harder to replace or reorganize.

The rules and process nodes use to agree on the next valid block (e.g., proof of stake). The majority chain following rules wins.

A smart contract address controlled by code. It cannot initiate transactions on its own; it runs when called by EOAs or other contracts.

An on-chain governance group that uses tokens or memberships to vote on proposals, budgets, or upgrades.

An app that uses smart contracts or on-chain data. The frontend is usually Web2; the backend logic/data lives on-chain.

On-chain financial services (swaps, lending, yield) run by smart contracts instead of centralized intermediaries.

The HD wallet path (e.g., m/44'/60'/0'/0/0) used to derive keys from a seed. Wrong path can show different addresses on restore.

In proof of work, the target that sets how hard it is to find a valid block hash. Adjusts periodically to keep block times on schedule.

Sending tiny amounts of tokens to many addresses, often to track movements or bait users into interacting with malicious tokens.

Elliptic Curve Digital Signature Algorithm. Used by many chains to prove control of a private key without revealing it.

Ethereum fee model with a base fee that burns and a tip (priority fee) to validators. Aims for predictable fees and elasticity.

An account controlled by a private key. Can initiate transactions, hold assets, and sign messages.

A URL to view a transaction, address, or block on a public block explorer—an independent source of truth.

A plan to restore a wallet safely: download from official link, offline room, type seed, verify derived address, and move funds if compromised.

What you pay miners/validators to process a transaction. On Ethereum, roughly gas used × (base fee + tip).

When a block is considered locked in. On PoW it is probabilistic (confirmations); on PoS with finality gadgets, reverting finalized blocks slashes large stakes.

A chain split. Temporary (reorg) when blocks compete; permanent (hard/soft) when rules change. Users must pick the canonical chain.

Max supply × current price. Shows valuation if every token existed; large FDV with big unlocks can signal future sell pressure.

A unit measuring work a transaction needs. More complex calls use more gas units; cost depends on gas price and base fee.

The maximum gas you allow a transaction to consume. Too low and it fails; too high and you might overspend if priced poorly.

What you’re willing to pay per unit of gas. Includes base fee (network-set) plus tip/priority fee to speed inclusion.

The first block of a chain, with no parent hash. Anchors all later history (e.g., Bitcoin’s block 0).

A scheduled cut in block subsidies (e.g., roughly every four years on Bitcoin), reducing new coin issuance over time.

Total proof-of-work performed per second across miners. Higher hashrate raises attack cost but can centralize if few entities control most of it.

Hierarchical deterministic wallet deriving many keys/addresses from one seed phrase using standard paths.

Wallet on an internet-connected device. Convenient for daily use; higher risk than cold storage for large holdings.

On-chain data or code that cannot be changed after deployment (or is extremely costly to change, e.g., via hard fork).

A base blockchain (e.g., Ethereum, Bitcoin). Provides security and consensus for higher layers.

A network built on top of a Layer 1 to scale throughput (rollups, sidechains). Inherits or depends on L1 security to varying degrees.

A recorded balance change on the blockchain. Blocks are sequences of ledger entries anyone can audit.

A client that verifies headers and proofs without storing full chain history, reducing resource needs.

A pool of tokens locked in a smart contract for swaps or lending. Liquidity providers earn fees/yield but face risks like impermanent loss.

The hard cap on how many tokens can ever exist (e.g., 21 million BTC). Some assets have no cap; others burn to reduce supply.

Each node’s queue of unconfirmed transactions waiting to be mined/validated. Fees rise when mempools are congested.

A single hash that commits to all transactions in a block. Any change to a transaction changes the root, signaling tampering.

Proving control of a private key without moving funds. Signed messages can be verified with the public key/address.

Value captured by controlling transaction ordering/inclusion (e.g., sandwich attacks, arbitrage). Users see it as slippage or failed txs.

A coordinator that aggregates miners’ hashpower and shares rewards. Smooths payouts but can concentrate control if pools get too large.

12–24 words that can recreate wallet private keys. Master backup; must stay offline and never be shared.

A wallet requiring multiple approvals (M-of-N) to move funds, reducing single-key compromise risk.

A token with a unique ID and metadata (often art, access, or utility). Provenance and ownership are on-chain.

A sender-specific counter that keeps transactions in order and prevents replay.

Data or actions recorded on the blockchain. Opposite of off-chain (e.g., server-side or custodial).

Tricking users into revealing seeds/keys or signing malicious transactions via fake sites, support chats, or cloned apps.

A secret number that can create valid signatures. Anyone with it can move associated funds.

A consensus mechanism where validators stake tokens to propose/attest blocks. Misbehavior can be penalized (slashing).

A consensus mechanism where miners expend compute to find valid blocks. Security comes from resource cost.

The non-secret key derived from a private key. Others use it to verify signatures or derive an address.

A vulnerability where a contract is called back before state updates finish, enabling repeated withdrawals unless guarded.

A short fork where recent blocks are replaced by a longer/valid chain. Shallow reorgs are normal; deep ones are risky.

A Layer 2 that batches transactions and posts proofs/data to Layer 1. Types include optimistic and ZK rollups.

Remote procedure call endpoint your wallet/DApp uses to talk to a node. Using trusted, correct RPC prevents wrong-network mistakes.

An isolated environment (often testnet or local) to experiment without risking real assets.

The smallest Bitcoin unit (0.00000001 BTC). Also Satoshi Nakamoto, the pseudonymous creator of Bitcoin.

Offline storage of the seed phrase (paper or metal). Avoid photos/screenshots/cloud; verify once and store securely.

Holding your own keys instead of relying on a custodian. Keys = control; loss or leak = loss of funds.

A separate chain that bridges to a main chain. Security depends on its own validators, not necessarily the main chain.

A cryptographic proof created with a private key that others can verify with the public key/address.

The difference between expected and executed swap price. High slippage can indicate MEV, low liquidity, or mis-set tolerances.

Code deployed on-chain that runs deterministically when called. Immutable or upgradeable depending on design.

A token pegged to a reference (often USD). Designs vary (custodial, collateralized, algorithmic) with different risk profiles.

A hash of the global state (accounts/storage) in a block. Changes if any account/storage changes.

A network for practice with valueless tokens. Use to learn and test without risking real assets.

Permission a token holder gives a contract to move tokens on their behalf. Unlimited approvals can be risky; revoke when unused.

Unique identifier of a submitted transaction. Use it on a block explorer to verify status, fee, from/to, and logs.

The same as nonce: sender’s transaction counter to keep ordering and prevent replay.

A participant in proof of stake who proposes/attests blocks. Staked tokens can be slashed for misbehavior.

Software or hardware holding private keys. It signs transactions and messages; assets stay on-chain.

See allowlist. A list of approved addresses for mints or access. The preferred term is allowlist.

A cryptographic proof that shows a statement is true without revealing the underlying data (used in ZK rollups and privacy tools).