The term 'reference structure' is a collective term for ontologies, topic maps, thesauri, keyword lists, etc. A reference structure is an ordered set of concepts with their properties and relations to each other, which is used for the purpose of making content findable.
A reference network is a set of reference structures that have been linked in such as way that a transparant whole is created for editors (content managers) and end-users alike. As a result of this linking, content that refers to concepts in individual reference structures can be accessed as if it forms part of a single collection.