Blockchain Vocabulary: 80 Terms Every Web3 Developer Must Know in English

Blockchain is a field where English precision matters enormously — smart contract code is law, audit reports identify critical vulnerabilities by name, and governance proposals are voted on by global communities. This guide covers the 80 terms you need to communicate confidently in Web3.

Blockchain Fundamentals

Block

A block is a record in a blockchain containing a batch of validated transactions, a timestamp, and a cryptographic hash of the previous block. Blocks are chained together in chronological order.

Chain

The chain is the sequence of linked blocks. Once a block is added to the chain, altering it requires recalculating all subsequent blocks — making the record tamper-evident.

Node

A node is a computer participating in a blockchain network. A full node stores the complete blockchain and validates transactions independently. A light node stores only block headers and relies on full nodes for validation.

Validator / Miner

A validator (in Proof of Stake networks) or miner (in Proof of Work networks) is a node that proposes and confirms new blocks. Validators stake cryptocurrency as collateral.

Immutability

Immutability means that once data is recorded on a blockchain, it cannot be altered or deleted without network consensus. This is a core property of public blockchains.

Distributed Ledger

A distributed ledger is a database shared and synchronised across many nodes without a central authority. Blockchain is one type of distributed ledger technology (DLT).

Byzantine Fault Tolerance (BFT)

BFT describes a system’s ability to continue operating correctly even when some nodes fail or act maliciously (Byzantine failures). Most consensus algorithms are designed to be BFT up to a threshold (e.g., one-third of nodes).

Consensus Mechanisms

Proof of Work (PoW)

In PoW, miners compete to solve a computationally expensive puzzle. The winner adds the next block and receives the block reward. Used by Bitcoin. Energy-intensive.

Proof of Stake (PoS)

In PoS, validators are chosen to propose blocks based on the amount of cryptocurrency they have staked. Used by Ethereum (post-Merge). More energy-efficient than PoW.

Finality

Finality refers to the point at which a transaction is considered irreversible. In PoW, finality is probabilistic (more confirmations = more certain). In some PoS systems, finality is deterministic.

Fork

A fork is a change to the blockchain protocol. A soft fork is backward-compatible. A hard fork is not — it creates a permanent divergence, potentially splitting the chain (e.g., Ethereum / Ethereum Classic).

Block Time

Block time is the average time between consecutive blocks. Bitcoin targets 10 minutes. Ethereum targets 12 seconds.

Cryptography

Private Key / Public Key

A private key is a secret number that proves ownership of an address and is used to sign transactions. A public key is derived from the private key and can be shared publicly. Never share your private key.

Wallet Address

A wallet address is a hashed version of the public key — the identifier you share to receive funds. Example: 0x742d35Cc6634C0532925a3b844Bc454e4438f44e

Digital Signature

A digital signature proves that a transaction was authorised by the holder of the private key, without revealing the key itself.

Seed Phrase (Mnemonic)

A seed phrase is a human-readable backup of a private key — typically 12 or 24 English words (BIP-39 standard). Controls full access to a wallet.

“Never store your seed phrase digitally or share it with anyone.”

Multi-sig (Multi-signature)

A multi-sig wallet requires multiple private keys to sign a transaction. Used for treasury security, requiring M-of-N signatures (e.g., 3-of-5).

Merkle Tree

A Merkle tree is a data structure where every leaf node holds a transaction hash and every parent node holds the hash of its children. The Merkle root in the block header summarises all transactions efficiently.

Zero-Knowledge Proof (ZK Proof)

A ZK proof allows one party to prove they know a value without revealing the value itself. Foundational to privacy-preserving protocols and ZK rollups.

Smart Contracts

Smart Contract

A smart contract is self-executing code deployed on a blockchain. It automatically enforces the terms of an agreement when predefined conditions are met — no intermediary required.

“The smart contract releases the payment to the freelancer once the client confirms delivery.”

Solidity

Solidity is the most widely used programming language for writing Ethereum smart contracts. Syntax resembles JavaScript/C++.

ABI (Application Binary Interface)

The ABI defines how to interact with a smart contract — what functions are available, what arguments they take, and what they return. Required for front-end integration.

EVM (Ethereum Virtual Machine)

The EVM is the sandboxed runtime environment where Ethereum smart contracts execute. All EVM-compatible chains (Polygon, BNB Chain, Avalanche C-Chain) run the same bytecode.

Gas / Gas Fee

Gas is the unit measuring computational effort required to execute operations on Ethereum. The gas fee is the ETH paid to validators for processing transactions. Gas price is measured in Gwei (10⁻⁹ ETH).

“Gas fees spiked to $200 per transaction during the NFT mint.”

Reentrancy

A reentrancy attack occurs when a malicious contract calls back into the victim contract before the first execution completes, allowing repeated withdrawals. The DAO hack (2016) exploited reentrancy, leading to the Ethereum hard fork.

Token Standards

ERC-20

The ERC-20 standard defines a fungible token interface — all tokens are identical and interchangeable. Used for most DeFi tokens (USDC, DAI, UNI).

ERC-721

The ERC-721 standard defines a non-fungible token (NFT) — each token is unique. Used for digital art, collectibles, and gaming items.

ERC-1155

ERC-1155 is a multi-token standard allowing a single contract to manage both fungible and non-fungible tokens efficiently. Widely used in gaming.

Upgradeable Contract / Proxy Pattern

An upgradeable contract uses a proxy pattern — users interact with a proxy contract that delegates calls to an implementation contract. Allows upgrading logic without changing the address.

DeFi (Decentralised Finance)

DeFi

DeFi refers to financial services built on blockchains using smart contracts — lending, borrowing, trading, and yield generation without banks or intermediaries.

Liquidity Pool

A liquidity pool is a collection of tokens locked in a smart contract to facilitate trading on a decentralised exchange. Liquidity providers (LPs) deposit tokens and earn trading fees.

AMM (Automated Market Maker)

An AMM is a smart contract that sets token prices algorithmically based on supply ratios in a pool, replacing traditional order books. The formula x * y = k (constant product) is used by Uniswap.

DEX (Decentralised Exchange)

A DEX enables peer-to-peer token swaps directly from wallets, without a central company holding custody of funds. Examples: Uniswap, Curve, Balancer.

Yield Farming

Yield farming is the practice of depositing tokens into DeFi protocols to earn rewards — trading fees, governance tokens, or interest.

Impermanent Loss

Impermanent loss is the temporary loss an LP experiences when the ratio of their deposited tokens changes relative to holding them. The loss becomes permanent if withdrawn before the ratio recovers.

TVL (Total Value Locked)

TVL is the total USD value of assets deposited in a DeFi protocol. A widely used metric for protocol size and adoption.

Liquidation

Liquidation in DeFi lending happens when a borrower’s collateral value falls below the required ratio. The collateral is automatically sold to repay the loan.

APY / APR

APY (Annual Percentage Yield) includes compound interest. APR (Annual Percentage Rate) does not. DeFi protocols often display APY to show higher numbers — check which metric is used.

NFTs

NFT (Non-Fungible Token)

An NFT is a unique digital asset whose ownership is recorded on a blockchain. Unlike currencies, NFTs are not interchangeable — each has distinct properties.

Mint

To mint an NFT is to create it — deploying a new token record on the blockchain, typically through a smart contract.

Floor Price

The floor price is the lowest asking price for an NFT in a given collection on the secondary market. A key measure of collection value.

Metadata / TokenURI

NFT metadata describes the token’s properties (name, image URL, traits). Stored off-chain (IPFS or centralised server) and referenced via a tokenURI in the contract.

Royalty

An NFT royalty is a percentage of secondary sale value that goes to the original creator automatically via smart contract.

Layer 2 Scaling

Rollup

A rollup is an L2 scaling solution that executes transactions off the main chain (L1) and posts compressed transaction data back to L1 for security.

Optimistic rollup — assumes transactions are valid; fraud proofs can challenge invalid transactions within a dispute window (e.g., Arbitrum, Optimism)
ZK rollup — generates a cryptographic validity proof for every batch (e.g., zkSync, StarkNet, Polygon zkEVM)

Sequencer

The sequencer is the entity in a rollup that orders and batches transactions before submitting them to L1. Centralised in many current rollups — decentralising the sequencer is an active area of development.

Data Availability

Data availability refers to ensuring that transaction data posted to L1 can be retrieved and verified. EIP-4844 (Proto-Danksharding) introduced blobs — cheaper temporary data storage on Ethereum for rollups.

DAOs & Governance

DAO (Decentralised Autonomous Organisation)

A DAO is an organisation governed by smart contracts and token holder votes, without traditional management hierarchy. Treasury, policy, and product decisions are made by community governance.

Governance Token

A governance token grants voting rights in a DAO. Holding more tokens typically means more voting power (though quadratic voting models exist to limit plutocracy).

Proposal

A proposal is a formal suggestion submitted to a DAO for a vote — e.g., allocating treasury funds, changing a protocol parameter, hiring a contributor.

Quorum

Quorum is the minimum participation required for a vote to be valid. If fewer than X% of tokens vote, the result is not binding.

Snapshot

Snapshot is a widely used off-chain gasless voting tool for DAOs. Votes are signed messages — no gas required — with results implemented on-chain by a multi-sig.

Temperature Check

A temperature check is an informal, non-binding poll to gauge community sentiment before a formal proposal is submitted.

Practical Phrases

In code reviews / audits:

“There’s a reentrancy vulnerability in the withdraw function — state should be updated before the external call.”
“The contract doesn’t validate that the caller is the token owner before minting.”
“This proxy pattern doesn’t include a storage collision guard.”

In DAO governance:

“I’m in favour of this proposal — the TVL growth justifies the additional liquidity incentives.”
“The quorum threshold wasn’t reached, so the vote is non-binding.”

In technical discussions:

“We’re deploying on an L2 to reduce gas costs for end users — we chose Arbitrum for its optimistic rollup security model.”

Practice

Test your Blockchain vocabulary with the Blockchain & Web3 exercise set — 5 exercises covering core terms, DeFi concepts, and smart contract vocabulary.

Explore the full Blockchain Developer learning path for exercises, interview prep, and scenario practice.