an ontology editor, is an Award Winning comprehensive tool for editing and manipulating complex ontologies that uses Controlled Natural Language. Fluent Editor provides one with a more suitable for human users alternative to XML-based OWL editors. It's main feature is the usage of Controlled English as a knowledge modeling language . Supported via Predictive Editor, it prohibits one from entering any sentence that is grammatically or morphologically incorrect and actively helps the user during sentence writing.