Basic Formal Ontology

What is BFO?

BFO is a top-level ontology that provides a common framework for describing the fundamental concepts of reality. It is used by over 700 ontology-based research projects across biomedicine, defense and intelligence, industrial manufacturing, and many other domains.

ISO Standardization

BFO 2020 is the latest version of BFO as standardized in ISO/IEC 21838-2:2021. This standard is part of a two-part series:

1. ISO/IEC 21838-1:2021 - Top-Level Ontologies (TLO)

   • Published August 2021
   • Specifies requirements for top-level ontologies
   • Available at ISO 71954

2. ISO/IEC 21838-2:2021 - Basic Formal Ontology (BFO)

   • Published November 2021
   • Standardizes BFO 2020 as a top-level ontology conforming to Part 1
   • Available at ISO 74572

The complete BFO 2020 content is freely available at ISO/IEC 21838-2, including:

• Excel files:

  • bfo-2020-terms.xlsx - Terms and relational expressions with definitions and examples
  • bfo-2020-iris.xlsx - IRIs for all classes and relations
  • bfo-2020-relations-table.xlsx - Table of all relations including inverses and reverses

• OWL files:

  • bfo-2020.owl - OWL in RDF/XML format
  • bfo-2020.ofn - OWL in functional syntax
  • bfo-2020-labeled.ofn - OWL in functional syntax with labels
  • bfo-2020-without-some-all-times.owl - OWL without binaryized relations

• Common Logic formalization:

  • Complete set of modules in CL format
  • temporalized-relations.cl - CL definitions of binary temporal relations

• Additional resources:

  • PDF folder: CL axiomatization in FOL syntax
  • Prover9 folder: Modules in Prover9 format
  • Model folder: Consistency proof models in multiple formats

New releases of BFO based on BFO 2020 are developed and maintained at BFO-2020 GitHub repository. You will always be able to find the most recent release of BFO in this repository.

For questions about BFO 2020, contact [email protected]

For BFO 2020 (# ISO standard) see here

Release information on BFO github site