A Multi-Axial Mindset for Ontology Design Lessons from Wikidata's Polyhierarchical Structure

TL;DR

This paper analyzes Wikidata's polyhierarchical, multi-axial ontology structure, highlighting its scalability and suitability for collaborative, evolving knowledge graphs, contrasting with traditional single-axis hierarchies.

Contribution

It introduces a detailed analysis of Wikidata's multi-axial design, demonstrating its advantages over traditional single-axis ontologies for scalable knowledge graph construction.

Findings

Wikidata's structure allows multiple classification axes simultaneously.

The multi-axial design supports scalable, modular ontology development.

This approach is well-suited for collaborative and evolving knowledge graphs.

Abstract

Traditional ontology design emphasizes disjoint and exhaustive top-level distinctions such as continuant vs. occurrent, abstract vs. concrete, or type vs. instance. These distinctions are used to structure unified hierarchies where every entity is classified under a single upper-level category. Wikidata, by contrast, does not enforce a singular foundational taxonomy. Instead, it accommodates multiple classification axes simultaneously under the shared root class entity. This paper analyzes the structural implications of Wikidata's polyhierarchical and multi-axial design. The Wikidata architecture enables a scalable and modular approach to ontology construction, especially suited to collaborative and evolving knowledge graphs.