📖 What is Universal Ontology Definition?

Universal Ontology Definition (UOD) is an open, standardized four-layer enterprise ontology framework designed to provide a unified conceptual modeling foundation for enterprise knowledge graphs, semantic layers, master data management, and AI Agent knowledge bases.

🔴 The Problem

Enterprise digitalization commonly faces:

• Inconsistent concept definitions — Different teams use different terms for the same objects, making cross-system reuse difficult.
• Industry knowledge silos — Industry-specific knowledge is scattered with no standardized extension mechanism.
• Customization vs. standardization conflicts — Enterprise-specific needs continuously erode the underlying structure.
• Platform lock-in — Ontology definitions tied to a single serialization format, limiting interoperability.

🟢 The Solution: Four-Layer Architecture

flowchart TD
    classDef layer3 fill:#f8f9fa,stroke:#dee2e6,stroke-width:2px,stroke-dasharray: 5 5,color:#495057
    classDef layer2 fill:#e9ecef,stroke:#ced4da,stroke-width:2px,color:#495057
    classDef layer1 fill:#e0f3ff,stroke:#0d6efd,stroke-width:2px,color:#0a58ca,font-weight:bold
    classDef layer0 fill:#f8f9fa,stroke:#dee2e6,stroke-width:2px,color:#6c757d
    classDef label fill:none,stroke:none,color:#6c757d,font-size:12px
    
    L3["<b>L3: Enterprise Customization Layer</b><br/><span style='font-size:13px'>Company A | Company B | Company C</span>"]:::layer3
    L2["<b>L2: Industry & Domain Extensions</b><br/><span style='font-size:13px'>Common | Consulting | Luxury | Finance | Manufacturing</span>"]:::layer2
    L1["<b>L1: Universal Enterprise Ontology Core (v2.0)</b><br/>Entity 🔸 Governance 🔸 Operational 🔸 Measurement"]:::layer1
    L0["<b>L0: Platform & Syntax Bindings</b><br/><span style='font-size:13px'>OWL/RDF | JSON-LD | GraphQL | SQL DDL</span>"]:::layer0

    L3 -. "Private extensions (Optional)" .-> L2
    L3 -. "Mandatory inheritance" .-> L1
    L2 -- "Pluggable domain models" --> L1
    L1 == "Binds to" ==> L0

✨ Key Features

• 🏗️ Four-Layer Separation — Stable semantic core, pluggable Industry and Domain Extension, free enterprise customization, and multi-platform bindings.
• 🛡️ Anti-Entropy by Design — 4 abstract domain roots, hard class caps, governance rules, and CI validation prevent ontology sprawl.
• 📐 Standardized Definition Format — Unified JSON Schema with lifecycle management (status, since, deprecated_since).
• 🔗 Inheritance & Extension — L2 extends L1, L3 extends L1+L2, with generalized domain/range relations.
• ⚙️ Platform Bindings — L0 provides ready-to-use OWL/RDF, JSON-LD, GraphQL, and SQL mappings.
• 🌍 Bilingual Support — All concepts include Chinese and English labels and definitions.
• 🤝 Community-Driven — Anyone can contribute Industry and Domain Extensions, platform bindings, or improve core definitions.

📁 Repository Structure

.
├── core/                       # L1 Universal Enterprise Ontology Core
│   └── universal_ontology_v1.json
├── extensions/                 # L2 Industry & Domain Extensions
│   ├── consulting/             #   └── Consulting Industry Extension
│   ├── luxury-goods/           #   └── Luxury Goods Industry Extension
│   └── _template/              #   └── Extension Contribution Template
├── enterprise/                 # L3 Enterprise Example
│   ├── acme-tech-solutions/    #   └── Sample Virtual Enterprise
│   ├── _template/              #   └── Enterprise Layer Template
│   └── README.md
├── platform/                   # L0 Platform & Syntax Bindings
│   ├── owl-rdf/                #   └── OWL 2 / RDF Turtle Serialization
│   ├── json-ld/                #   └── JSON-LD Context Definition
│   ├── graphql/                #   └── GraphQL Schema Definition
│   ├── sql/                    #   └── PostgreSQL DDL Mapping
│   └── _template/              #   └── Platform Binding Template
├── scripts/                    # CI & Governance Automation
│   ├── validate_governance.py  #   └── L1 Governance Rule Validator
│   └── json_to_owl.py          #   └── JSON → OWL/RDF Turtle Converter
├── docs-site/                  # MkDocs Documentation Site Source
└── schema/                     # JSON Schema Validation
    ├── core_schema.json
    └── extension_schema.json

🚀 Quick Start

1️⃣ Understanding Core Ontology

L1 v2.0 defines 24 classes (4 abstract domains + 20 concrete) and 12 generalized relations, organized into 4 semantic domains:

2️⃣ Using Platform Bindings (L0)

Choose the binding that matches your technology stack:

3️⃣ Using Industry & Domain Extensions

Browse the extensions/ directory and select the appropriate industry package. Each extension declares its parent through the extends field:

{
  "layer": "L2_consulting_industry_extension",
  "version": "1.0.0",
  "extends": "L1_universal_organization_ontology",
  "classes": [
    {
      "id": "ConsultingFirm",
      "label_zh": "咨询公司",
      "parent": "Organization",
      "definition": "An enterprise entity providing professional consulting services"
    }
  ]
}

4️⃣ Contributing a New Extension

1. Copy extensions/_template/ as your starting point.
2. Follow the Extension Development Guide.
3. Validate against schema/extension_schema.json.
4. Submit a Pull Request! (See CONTRIBUTING.md)

📚 Full Ontology Creation & Update Guide

For a comprehensive, step-by-step guide on creating or updating ontologies at any layer (L2/L3), including inheritance, validation, format conversion, and version management, see README_CN.md — Ontology 创建与更新完整指南.

💡 Pro Tip: A working L3 sample is available at enterprise/acme-tech-solutions/ — a fictional technology consulting company demonstrating the full workflow.

🗂️ Available Industry & Domain Extensions

Industry	Directory	Classes	Relations	Status
Consulting	extensions/consulting/	40+	34
Luxury Goods	extensions/luxury-goods/	38	14

🌟 We're looking for community contributions! Finance, Manufacturing, Retail, Healthcare, Education, and more.

⚙️ Available Platform Bindings

Platform	Directory	Format	Status
OWL/RDF	platform/owl-rdf/	Turtle (.ttl)
JSON-LD	platform/json-ld/	Context (.jsonld)
GraphQL	platform/graphql/	Schema (.graphql)
SQL DDL	platform/sql/	PG DDL (.sql)

🌟 Want more? Protobuf, Avro, Neo4j Cypher, and more are welcome contributions!

🤝 Contributing

We welcome all contributions! Please read CONTRIBUTING.md to learn about:

• Proposing changes to the Core Ontology
• Submitting new Industry & Domain Extensions
• Contributing new Platform Bindings
• Coding standards and PR workflow

📄 License & Acknowledgments

License

This project is licensed under the Apache License 2.0. You are free to:

• ✅ Use commercially
• ✅ Modify and distribute
• ✅ Build private L3 enterprise layers on top

Acknowledgments

The ontology design draws inspiration from:

• OWL 2 Web Ontology Language
• RDF 1.1 Concepts and Abstract Syntax
• Schema.org
• ArchiMate