# The Ontology Lookup Service is a spin-off of the PRIDE project, which required a centralized query interface for ontology and controlled vocabulary lookup. While many of the ontologies queriable by the OLS are available online, each has its own query interface and output format.

# The OLS provides a web service interface to query multiple ontologies from a single location with a unified output format.

# The OLS can integrate any ontology available in the Open Biomedical Ontology (OBO) format.