Terms and meanings can be organized according to different principles. These principles are often represented as the “semantic ladder”. The higher the organization principle is on the ladder, the more semantics the model also contains (and the more effort that must be put into the creation).
On the bottom step is the organization of meanings in a glossary. This is a simple list of words and their explanations. Glossaries are already used in many companies today. One step higher are the taxonomies. Here, the words are not only listed but they are placed in an – unspecified – hierarchical structure. Taxonomies are also often used in content management.
A thesaurus, in turn, is a controlled vocabulary for concepts that are placed in a hierarchical relationship with one another as a broader term and narrower term. Semantic networks mark additional concept relations beyond purely hierarchical relations. For example, these can be relationships such as “opposite”, “X contains Y”, or even “X is suitable for Y”. Finally, on the top step are ontologies. They are explicit, formal specifications of a common conceptualization. Ideally, ontologies can therefore cover all semantic relationships of a topic.