What are the Differences Between a Vocabulary, a Taxonomy, a Thesaurus, an Ontology, and a Meta-Model?
http://www.metamodel.com/article.php?story=20030115211223271

Pidcock, Woody
Metamodel.com
2003

Abstract:

Taxonomies and Thesauri may relate terms in a controlled vocabulary via parent-child and associative relationships, but do not contain explicit grammar rules to constrain how to use controlled vocabulary terms to express (model) something meaningful within a domain of interest. A meta-model is an ontology used by modelers. People make commitments to use a specific controlled vocabulary or ontology for a domain of interest.