Cross-language Ontology Learning: Incorporating and Exploiting Cross-language Data in the Ontology Learning Process Hans Hjelm Think of the frustrating experience of running into circular definitions when looking up a word in a dictionary. Yet – how do we convey the meaning of a word without referring to meanings of other words? In ontologies — the object of study in this thesis — this is exactly what we find: words (or concepts) defined by their position in a hierarchy of other words and the relations that hold between them.