A concept scheme is a way to group  several concepts and corresponds roughly to the notion of an individual thesaurus, classification scheme, subject heading system or other knowledge organization system.

Semantic relationships (links) between SKOS concepts may also be viewed as part of a concept scheme. The class skos:ConceptScheme refers to concept schemes. The class has the following properties:

  1. skos:hasTopConcept. It links a concept scheme to the SKOS concept(s) which are topmost in the hierarchical relations for that scheme
  2. skos:inScheme. It relates a concept to a concept scheme in which it is included.
  3. skos:topConceptOf. It elates a concept to the concept scheme that it is a top level concept of.
Graphical representation of concept scheme properties. 

Figure: Graphical representation of concept scheme properties.