BFO

Basic Formal Ontology (BFO) is a top-level ontology used in ontology engineering and biomedical informatics. It provides a minimal, philosophically informed foundation intended to support interoperability and reuse across domain-specific ontologies. BFO is widely adopted within the Open Biomedical Ontologies (OBO) Foundry and serves as a common framework for grounding domain ontologies that describe biological, medical, and related information.

Structure and core concepts: BFO defines a small set of domain-neutral categories and relationships that can be expressed in formal logics such as OWL. The central distinction is between continuants, which persist through time while maintaining identity, and occurrents, which are processes or events that unfold over time. Within continuants, BFO further differentiates independent continuants (entities that can exist on their own) from dependent continuants (qualities, dispositions, or roles that depend on other entities). This foundational partitioning aims to support consistent classification and reasoning across diverse domains.

Purpose and use: The primary aim of BFO is to provide a shared ontological substrate on which domain ontologies can align, reason about, and interoperate with each other. By adhering to BFO, ontologies can achieve clearer semantics, enabling cross-ontology queries and data integration. BFO is especially influential in biomedicine, where many ontologies build upon its upper-level structure to ensure consistency with other interoperable resources.

Development and scope: BFO is developed and maintained by an international community of researchers and practitioners associated with the OBO Foundry. While domain-neutral, its formal commitments influence modeling choices in many biomedical and information science projects. It is not intended to replace domain taxonomies but to underpin them with a coherent, testable foundation that supports automatic reasoning and integration.