RELExO (Relational Exploration for Learning Expressive Ontologies) is a tool for reasoner-aided relational exploration of OWL DL ontologies, that has been developed to support the acquisition and refinement of complex class descriptions.

Johanna Völker, Sebastian Rudolph. Lexico-Logical Acquisition of OWL DL Axioms - An Integrated Approach to Ontology Refinement. In Raoul Medina and Sergei Obiedkov, Proceedings of the International Conference on Formal Concept Analysis (ICFCA), Springer, February 2008.

Homepage: http://relexo.ontoware.org