Thesaurus

A Thesaurus is a controlled vocabulary that groups words together to provide definition and meaning.   In Information Science this is often a structure based around and agreed label or Preferred Term which than has relationships to other terms such as a synonym relationship (using a "Use/Used For" or USE/UF relationship) or an associative relationship ("Related To" or RT/RT).

The Preferred Terms my be organized hierarchically, in which case this becomes and extension to a pure taxonomy.