Relation Ontology



This is the reference guide for the OBO Relation Ontology (RO).

RO is a collection of relations intended primarily for standardization across ontologies in the OBO Foundry and wider OBO library. It incorporates core upper-level relations such as part of (BFO:0000050) as well as biology-specific relationship types such as develops from (RO:0002202).

Browsing and Download

  • Browse on OLS: OLS (click properties tab)
  • Browse on OntoBee: OntoBee

Currently the optimal way to browse RO is to download Protege and load the owl files.

Use the following URIs to download this ontology:


The OWL product is more expressive than the OBO format one, and includes additional axioms.

See also: