There are many different types of controlled vocabularies, the most common among them are: Thesaurus - a type of controlled vocabulary used in information systems that organizes concepts in hierarchical and/or associative relationships and provides their semantic definitions Classification schema - a system that based primarily on classifying things or concepts into groups or classes with a detailed explanation of those classification methods Subject heading list - a list of terms describing subjects in information system Taxonomy - a system that organizes things and concepts in groups based on their common characteristics and/or differences Terminology - a list of terms used to describe concepts in a certain domain Glossary - an alphabetical list of terms with their explanation used in a specific context