Semantic Network (Relational Vocabularies)

Definition, description and example of a semantic network

Definition, description and example of a semantic network

Flat VocabulariesA managed list of acceptable metadata terms that associates acceptable values with particular metadata elements. Flat vocabularies include authority files, glossaries, dictionaries, code lists, and gazetteers. Related Guide Multi -Level Vocabularies Relational VocabulariesManaged list of acceptable terms that makes use of relationships between metadata terms. Relational vocabularies include thesauri, semantic networks and ontologies. Related Guide
Authority File Glossary Dictionary Gazetteer Code List Taxonomy Subject Heading Thesaurus Semantic Network Ontology

Semantic Network (Relational Vocabulary)


A type of relational controlled vocabularyA managed list of terms. In the context of vocabularies, management typically includes careful selection of terms, maintenance of terms over time (i.e. addition, deprecation, modification), and presentation of the vocabulary in an accessible format. Related Guide consisting of lists of valuesMetadata values are the content connected to metadata labels in a metadata element. For example, if the metadata label is "date", the metadata value could be "May 13, 2007". Related Guide/concepts and directed relationshipsConnections between metadata terms within a vocabulary. These relationships can connect terms by scope, provenance, or other well-defined criteria..


Semantic networks can be thought of as super-thesauri. Each network can be represented in a directed graph of concept nodes connected by relations established in the NISONational Information Standards organization standardA set of documented rules which define the creation of metadata by providing a combination of terminology (vocabularies), syntactical rules, format rules, and other requirements. Metadata standards are approved, published and governed by a formal body or organization with broad community-based representation (international or national). Related Guide, along with additional relations such as whole-part, cause-effect, or parent-child relationships. Semantic networks tend to deal more in abstractions than concrete terminology.

A finite list of relations used in semantic networks does not exist. Semantic network relations can extend to provenance

The record of how a particular value or record came to be. Provenance can include things like when, by whom, and how the item was created or modified.

(parent-child), genesis (cause-effect) and complexity (whole-part). There are also relations for opposites, antonyms, complementary concepts, possessive, passive, and others. This is in stark contrast to the clear articulation of a finite set of relations (largely based on scope), which are articulated in ANSIAmerican National Standards Institute /NISO Z39.19 - 2003 for thesauri.

Information technology experts tend to use semantic networks to establish complex search interfaces, which can help a user locate the most appropriate results based on the search term. Since semantic networks describe complex relationships, the search interface can be programmed to interpret the user entry into various nodes, which are included in a semantic network. The resulting search is more exhaustive than that provided by a multi-level set of values, because the system can be set up to return results from different levels or categories based upon relations.

Note: There is extensive research about the development and use of semantic networks in the fields of linguistics, psychology, and philosophy.


Example of a simple semantic network

This very simple diagram of a semantic network illustrates the directed nature of relationships. For example, using this diagram, you can make the statement "A fish is an animal that lives in the water." Or, "A bear is a mammal (a type of animal with a vertebra) that has fur."

Suggested Citation

2011. "Semantic Network (Relational Vocabularies)." In The MMI Guides: Navigating the World of Marine Metadata. Accessed March 27, 2017.