Ethereum glossary
Gas fees, smart contracts and validators. Decode the Ethereum terms that turn up in wallet prompts, dev chats and staking discussions.
Event log
Data emitted during contract execution that applications can read from transaction records.
EVM
The Ethereum Virtual Machine, which executes Ethereum contract bytecode according to shared rules.
Externally owned account
An Ethereum account whose transactions are authorized by a private key, often abbreviated EOA.
Function selector
The first four bytes identifying a function in a standard Ethereum ABI-encoded call.
Gas
The unit Ethereum uses to measure the computation and other resources a transaction consumes.
Gas limit
The maximum amount of gas allowed for a transaction or block, depending on the context.
Gas price
The amount of ether paid per unit of gas consumed by an Ethereum transaction.
Gwei
A unit equal to one billion wei, commonly used to quote Ethereum gas prices.
JSON-RPC
A JSON-based request and response format commonly used by applications to communicate with blockchain nodes.
MEV
Maximal extractable value: value available through controlling transaction inclusion, exclusion or ordering beyond ordinary rewards and fees.
Opcode
A basic instruction understood by a virtual machine or scripting system.
Paymaster
An ERC-4337 contract that can pay gas costs for eligible smart-account operations.
Permit
A signed authorization that lets someone submit an ERC-20 allowance change on the token owner's behalf.
Priority fee
The part of an Ethereum transaction’s gas price paid to the block proposer above the base fee.
Proxy contract
A contract that forwards calls to implementation code while retaining its own address and storage.
Revert
An execution failure that rolls back changes made by the affected contract call.
RPC provider
A service giving wallets and applications access to blockchain node APIs.
Slot
A scheduled time interval in which a proof-of-stake network may produce a block.
Smart contract
A program on a blockchain that executes defined rules when it is invoked.
Solidity
A programming language commonly used to write smart contracts that compile to EVM bytecode.
State root
A cryptographic commitment to blockchain state using its defined authenticated data structure.
Transaction nonce
An Ethereum account’s sequential transaction counter, used to order transactions and prevent replay.
Transaction receipt
A record of an included Ethereum transaction’s execution result, including status, gas use and logs.
Typed-data signing
Signing structured Ethereum messages using a format such as EIP-712.
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