Term	Definition	See
Cypher	Query language for property graph databases	The Graph Space
Global Graph Algorithm	An algorithm that operates on the entire graph (e.g. PageRank, community detection, connected components)	Local vs Global
Aggregate NoSQL Store	NoSQL database organizing data around self-contained chunks (key-value, document, or column-family)	Modeling Connectivity
Graph	A collection of nodes and relationships connecting them	The Concept of Graph
Graph Compute Engine	An engine for offline batch analytics over graph data (like OLAP)	The Graph Space, Graph Compute Engine
Graph Database	An online CRUD database exposing a graph data model, optimized for OLTP	The Graph Space, Graph Database
Hypergraph	A graph model where a single edge can connect more than two nodes	The Graph Space
Index-free Adjacency	Connected nodes physically point to each other, O(1) traversal per hop	Graph Database
Local Graph Operation	Starts at a specific node and traverses outward, touching a small portion of the graph	Local vs Global
Native Graph Storage	Storage engine purpose-built for graphs (vs serializing into relational/other backends)	Graph Database
Node	An entity in a graph, can hold properties (key-value pairs)	The Concept of Graph, The Property Graph Model
Pregel	Google’s paper describing a distributed graph compute engine, basis for most distributed implementations	Graph Compute Engine
Property	A key-value pair attached to a node or relationship	The Property Graph Model
Property Graph	The most popular graph model variant, nodes and relationships with properties	The Property Graph Model, The Graph Space
Relationship (Edge)	A named, directed connection between two nodes, can hold properties	The Concept of Graph, The Property Graph Model
Relationship Chain	Doubly linked lists of relationships connecting a node to its neighbors on disk	Native Graph Storage
Write-Ahead Log	Durability mechanism: Changes are logged before being applied to store files	Transactions, Availability, Scale

Term	Definition	See
Digital Signature	Encrypted data blocks proving information came from a trusted source	The Semantic Web
Equivalence Statement	Explicit links between different names for the same concept across databases (e.g. “zipcode” = “postal code”)	Semantic Web
Inference Rules	Logical deductions encoded in ontologies (e.g. “if X is in city Y, and Y is in state Z, then X is in state Z”)	Semantic Web
Knowledge Representation	Representing a knowledge base in a machine-readable fashion	The Semantic Web
Ontology	A document formally defining relations among terms: Taxonomies, inference rules, and equivalence relations	Semantic Web, The Graph Space
Proof Verification	Verifying that claims are logically inferred from trusted sources via exchangeable mathematical proofs	The Semantic Web
RDF	Resource Description Framework: Triple-based model (subject-predicate-object) encoding meaning via URIs	Semantic Web, The Graph Space
Semantic Preservation	Extracting universal logic from systems while discarding system-specific instructions, losing as little meaning as possible	The Semantic Web
Semantic Web	Extension of the WWW adding machine-readable meaning to data, enabling computer-human cooperation	Semantic Web
Software Agent	Software that harvests data from diverse sources, processes it, and exchanges results with other agents	The Semantic Web
SPARQL	Query language for RDF data	The Graph Space
Taxonomy	Class hierarchies (classes and subclasses) and their relations within an ontology	Semantic Web
URI	Unique identifier tying a concept to a discoverable definition, solving ambiguity across systems	Semantic Web
XML	Adds arbitrary structure to documents via custom tags, structure without meaning	Semantic Web