ontologies

Ontologies is the plural of ontology, which in philosophy refers to the study of being and existence—the nature of what exists and how things that exist relate to each other.

In computing and information science, an ontology is a formal framework for organizing knowledge within a domain, defining concepts, categories, and their relationships so that data can be shared and processed consistently.

The researchers compared different ontologies for classifying medical conditions.

A single field may have competing ontologies that carve up the conceptual territory differently.