This page includes definitions for several key terms and concepts referred to throughout this documentation. [This page is incomplete.]

General terms


The existing Ethereum 1.0 protocol.

Proof-of-Stake (PoS)

The PoS concept states that a person can mine or validate block transactions according to how many coins they hold. This is a vastly improved iteration on the Proof-of-Work (PoW) system, which relied on immense amounts of computational power to advance the state of the blockchain.


Most often refers to an individual validator client instance, but can also refer to an individual that is physically managing a validator client.

Proposal (propose)

The process of creating and adding new blocks to the beacon chain.

Attestation (attest)

The process of voting on the validity of newly created blocks on the beacon chain.

Technical terms

Key-value store

A data storage paradigm designed for storing, retrieving, and managing hash tables.

Fork choice rule

A fork choice rule is a function evaluated by the client, that takes, as input, the set of blocks and other messages that have been produced, and outputs to the client what the “canonical chain” is.

State transition function