pezkuwi-subxt/polkadot/roadmap/implementers-guide/src/glossary.md

Glossary

Here you can find definitions of a bunch of jargon, usually specific to the Polkadot project.

• BABE: (Blind Assignment for Blockchain Extension). The algorithm validators use to safely extend the Relay Chain. See the Polkadot wiki for more information.
• Backable Candidate: A Parachain Candidate which is backed by a majority of validators assigned to a given parachain.
• Backed Candidate: A Backable Candidate noted in a relay-chain block
• Backing: A set of statements proving that a Parachain Candidate is backable.
• Collator: A node who generates Proofs-of-Validity (PoV) for blocks of a specific parachain.
• Extrinsic: An element of a relay-chain block which triggers a specific entry-point of a runtime module with given arguments.
• GRANDPA: (Ghost-based Recursive ANcestor Deriving Prefix Agreement). The algorithm validators use to guarantee finality of the Relay Chain.
• Inclusion Pipeline: The set of steps taken to carry a Parachain Candidate from authoring, to backing, to availability and full inclusion in an active fork of its parachain.
• Module: A component of the Runtime logic, encapsulating storage, routines, and entry-points.
• Module Entry Point: A recipient of new information presented to the Runtime. This may trigger routines.
• Module Routine: A piece of code executed within a module by block initialization, closing, or upon an entry point being triggered. This may execute computation, and read or write storage.
• Node: A participant in the Polkadot network, who follows the protocols of communication and connection to other nodes. Nodes form a peer-to-peer network topology without a central authority.
• Parachain Candidate, or Candidate: A proposed block for inclusion into a parachain.
• Parablock: A block in a parachain.
• Parachain: A constituent chain secured by the Relay Chain's validators.
• Parachain Validators: A subset of validators assigned during a period of time to back candidates for a specific parachain
• Parathread: A parachain which is scheduled on a pay-as-you-go basis.
• Proof-of-Validity (PoV): A stateless-client proof that a parachain candidate is valid, with respect to some validation function.
• Relay Parent: A block in the relay chain, referred to in a context where work is being done in the context of the state at this block.
• Runtime: The relay-chain state machine.
• Runtime Module: See Module.
• Runtime API: A means for the node-side behavior to access structured information based on the state of a fork of the blockchain.
• Secondary Checker: A validator who has been randomly selected to perform secondary approval checks on a parablock which is pending approval.
• Subsystem: A long-running task which is responsible for carrying out a particular category of work.
• Validator: Specially-selected node in the network who is responsible for validating parachain blocks and issuing attestations about their validity.
• Validation Function: A piece of Wasm code that describes the state-transition function of a parachain.

Also of use is the Substrate Glossary.