The Suggested Upper Merged Ontology (SUMO) is a free, formal upper ontology with many associated tools, translations, explanatory documents and domain ontologies. It is owned by IEEE. SUMO and all domain ontologies consist of 20,000 terms and 60,000 axioms. These consist of SUMO itself, the MId-Level Ontology (MILO), and ontologies of Communications, Countries and Regions, Distributed computing, Economy, Finance, Engineering components, Geography, Government, Military, North American Industrial Classification System, People, Physical elements, Transnational Issues, Transportation, Viruses, World Airports A-K, World Airports L-Z. All terms are formally defined. Meanings are not dependent on a particular inference implementation. An inference and ontology management system however is provided. An additional system that supports visual editing, and does a better job of displaying the ontologies, especially in non-Western languages is the KSMSA system. SUMO is the only formal ontology (according to the website) that has been mapped to the entire WordNet lexicon. SUMO is written in the SUO-KIF language.