A thesaurus is a controlled and structured vocabulary where concepts are represented by terms. In a multilingual thesaurus like ELSST, the same concept is represented by a single Preferred Term in each of the languages of the thesaurus. Optionally, one or more alternative labels or Entry Terms can be linked to a Preferred Term in each language version of the thesaurus.
Each concept in ELSST is identified by a dereferenceable Uniform Resource Identifier (URI) (= URL).
Each concept of the thesaurus can be semantically related to other concepts within the thesaurus. Hierarchical relations are represented by Broader Concepts and Narrower Concepts, while non-hierarchical associative relations are represented by Related Concepts.
ELSST concepts may also be associated with different types of note field: Definition, Definition Source, Scope Note, and History Note. A Definition describes the meaning of the concept within the thesaurus, while a Scope Note provides advice on term usage to either indexers or searchers. A Scope Note may also clarify the meaning of the concept with respect to other concepts in the thesaurus. A History Note records the date of introduction or the changes made to an existing term. A full list of Definition Sources can be found in the Bibliography of Definition Sources.