Defining a VOCABULARY, & Other Related Terms

A fundamental component of any Enterprise Architecture is the set of key terms and concepts that are a part of the enterprise domain.  These terms and their associated definitions serve to falilitate understanding, foster consensus, and minimize confusion within and outside the enterprise.  The collections of terms and definitions may be called by different names, depending on how they are organized and presented.  Here is a quick and dirty overview of some of these collections of terms.

VOCABULARY = The list of terms and concepts used within a domain, with their associated definitions.  Ideally, there should be only one definition per term and only one term per definition, though there may exist situations where a single term has more than one definition.  In these instances, it becomes necessary either to designate one definition as the "authoritative" one and annotate all others as alternatives, or to define the specific conditions under which the alternative definitions apply.

THESAURUS = A list of synonyms (i.e., terms with the same or very similar meanings) within a domain.  A thesaurus also may contain antonyms--terms with opposite meanings.

TAXONOMY = A listing of the terms and concepts within a domain showing the hierarchical relationships among them.  These hierarchical relationships usually can be expressed as "is a child of", “is a parent of", “is a part of", "is composed of", or similar parent-child or whole-part expressions.  Ideally, a term should be the child of only one parent within a single taxonomy, though it can be included in multiple taxonomies.  A taxonomy has to include some attribute (or set of attributes) that are used to organize the instance terms and concepts.  It is possible; however, to apply different attributes to the same set of things and get totally different taxonomies.  For example, starting with the set of all people in the world, a different taxonomy would be produced by applying the attribute GENDER than would result from the attribute NATIONALITY, or LANGUAGE, or EDUCATION LEVEL, or OCCUPATION, or MARITAL STATUS, etc.

ONTOLOGY = A listing of the "things" that exist within a domain, and the relationships among those things.  The types of relationships possible go beyond the parent-child or whole-part relationships shown in a taxonomy.  However, they must be clearly defined, and can be thought of as "methods" that relate one thing to another (e.g., an OBJECT occupies a LOCATION).

LEXICON = A listing of equivalent terms and concepts in two or more languages or domains.

DICTIONARY = An alphabetical listing of words from a particular language with their definitions, origins, pronunciations, synonyms, antonyms, and other information. Dictionaries may come on two “flavors”: Generalized (i.e., containing all words) or Directed (i.e., limited to those words within a specific knowledge, subject, or functional area).  A Directed Dictionary is also called a Specialized Dictionary.

 
DATA ELEMENT DICTIONARY = A listing of the data elements, their definitions, associations/relationships, and associated business rules extracted from a data model or schema.