Part of Stem. Every word the specification relies on is defined exactly once. Terms Stem introduces have their own definition page or schema page here; terms Stem leaves unchanged link to the official documentation.

Identity and data

Term	Meaning	Defined at
blob	A signed DAG-CBOR value named by its CID. Unchanged.	Signed blobs
principal	A public key in its byte form; an account or device identity. Unchanged.	Principal
CID, timestamp, signature	The content identifier, the millisecond timestamp and the signature of a blob. Unchanged.	CID, Timestamp, Signature
resource	A mutable thing with a stable identity, rebuilt from blobs.	Resource
node	The identity and placement record of a resource; the same thing as the resource seen from the blob side.	Node
node id	The stable id of a node: the CID of the Node blob that created it (`bafyrei…`), carried by every later Node blob for the node and used in the mutable URL `hm://<owner>/<nodeId>`.	Node id
space	An account's namespace: the node tree under its space root.	Space
space root	The one node of a space whose creating Node blob is deterministic from the owner's key; owner-only; carries the profile attributes and the home document; `hm://<owner>` is its alias.	Space kind
kind	The definition of a resource type: state representation, schema, naming, access mode, retention, links.	Kind
state	The current value of a resource, computed from the targets of its Node blobs.	State
version	An immutable reference to one state: the sorted head CIDs or the Snapshot CID.	Version
Node blob	The signed blob that declares a resource's identity, kind, placement, state target, causal position and access mode.	Node
target	The state declaration inside a Node blob: heads, snapshot, tombstone or redirect.	Node target
Change	A signed delta in a document's CRDT graph. Layout unchanged.	Change, library Change
Snapshot	A signed blob holding the complete state of a resource.	Snapshot
block, file	The content tree inside a document, and UnixFS data. Unchanged.	Blocks, Files
schema	A Hypermedia Schema value; the meta-schema describes itself. Unchanged.	Schema

Placement and addressing

Term	Meaning	Defined at
placement	A node's parent and name; the placement tree is for naming and addressing only.	Placement
name	A node's relative name inside its parent: one path segment.	Name
path, pretty path	A slash-joined chain of names from the root; derived, never identity.	Path
node reference	A space, a node id and an optional version, naming a resource wherever a link, redirect or policy needs one.	Node reference
hm:// URL	The address grammar. Unchanged except that a first segment holding a node id (`bafyrei…`) addresses that node, and the `n` parameter carries the node id beside a pretty path.	URLs, Path
redirect	A Node target that sends readers to another node.	Redirect target
tombstone	A Node target that deletes the resource while keeping its id taken.	Tombstone target

Authority and audience

Term	Meaning	Defined at
grant	A signed statement that an audience holds an access level over a subject.	Grant
access level	One of `sync`, `read`, `write`, `admin`, in that order.	Access level
subject	What a grant covers: a node with or without its subtree, or a group.	Subject
audience	The set of principals a grant speaks about: everyone, a key, a group, a bearer secret, or the readers of a node.	Audience
readers	The computed set of principals that may read a node.	Readers
access mode	How a node derives its readers: inherit, own or target.	Node access
group	A permanode whose members are the holders of live grants on it.	Group
revocation	A signed statement that cuts a grant.	Revocation
authority graph	The grants and revocations of a space, evaluated in two passes.	Authority graph
proof	The grant a blob relies on for its authority; a hint for fetching, not an input to evaluation.	Proof
owner	The account whose key is the space; a permanent admin of the space root and so of every node under it.	Space

Sync and bookkeeping

Term	Meaning	Defined at
scope	What a sync conversation is about: a space, a node, a depth and a set of facets.	Scope
scope set	The blobs a peer holds for a scope that the requesting peer may read.	Scope set
policy	An account's sync rules, a Snapshot resource shared among its devices.	Policy kind, Policy rule
peer, peer id	A device connection on the network, identified by a libp2p key that never signs content.	Peer id, Network
authority peer	A peer that holds write, admin or sync on a space, or is its declared site.	Authority peer
trusted peer	A peer of an account the local account has joined, or that holds a grant from it.	Trusted peer
site	A peer that publishes a space on the web under a relationship signed by both sides.	Site
transfer	One batch of blobs received from a peer under a claimed scope, with per-blob verdicts.	Transfer
disclosure	One blob served to a peer, with the basis that allowed it.	Disclosure
basis	Why a serve was allowed: public, a grant, a bearer secret, a site relationship, or an offer in progress.	Basis
range-based set reconciliation	The fingerprint-and-split comparison of two sorted sets. Unchanged.	Network, Range

Indexing

Term	Meaning	Defined at
handler	The one indexing routine every blob passes through, driven by kind descriptors.	Handler
link	A derived, typed edge from a blob to a blob or a resource.	Link, Link kind
fact	An indexed statement about a resource, marked signed or derived.	Fact
stash	A stored blob not yet applied because a dependency or a grant is missing. Unchanged.	Glossary
HM24	The protocol that ships today, with path-keyed Refs and Capabilities.	The Hypermedia Protocol

Words Stem does not use

Stem pages do not say Ref, capability, visibility, generation, named root, inode, permission, subscription, discovery or Bitswap except when describing HM24. The replacements are Node, grant, audience and readers, prev, resource, node id, access level, policy rule, Sync and Fetch.