This section is only a draft, but hopefully it provides some useful information.

The Common Vocabulary Translator (CVT) translates the nearly 15,000 Nomenclature 4.0 terms into a simpler Common Vocabulary terms used in the Digital Archive. The hierarchy for a single Nomenclature can be up to six levels deep, though not every term uses all six levels. The levels are:

  1. Category
  2. Class
  3. Sub Class
  4. Primary term
  5. Secondary term
  6. Tertiary term

Here are three examples of Nomenclature terms:

Category 01: Built Environment Objects
    Building Components
        Construction Materials
            Building Stone
                Dimension Stone
                    Dressed Stone

Category 07: Distribution & Transportation Objects
    Land Transportation T&E
        Animal-Powered Vehicles

Category 08: Communication Objects
    Documentary Objects
        Graphic Documents

The Common Vocabulary Translator (CVT) translates Nomenclature terms into a simpler Common Vocabulary terms strings based on a set of translation rules that will be explained later. The rules tell the CVT how to translate the hierarchy shown above into the strings shown below.

Object, Built Environment, Building Stone, Dimension Stone, Dressed Stone

Transportation, Carriage, Buckboard

Image, Photograph, Negative

Hierarchy Terminology


The deepest element in any hierarchy is called the leaf term. In Nomenclature, every leaf term is unique which makes it possible to determine the full hierarchy from just the leaf term. In the examples above, the leaf terms are Dressed Stone, Buckboard, and Negative.

To ensure that each leaf term is unique, Nomenclature add words to leaf terms to distinguish them from other leaf terms. For example, in addition to the leaf term Negative, there are leaf terms for Glass Plate Negative, Roll Film Negative, and Sheet Film Negative.

The CVT preserves Nomenclature leaf terms -- it never translates them -- to ensure that they are the same as and can be matched with the same terms used in other applications such as PastPerfect.

Nomenclature 4.0 supports leaf terms in both inverted and natural order. Examples of inverted order are Negative, Glass Plate, Negative, Roll File, and Negative, Sheet Film. The CVT uses the natural order terms when generating Common Vocabulary terms for the Digital Archive.


To convert Nomenclature terms to Common Vocabulary terms, the CVT puts special emphasis on the tail of the hierarchy. The tail consists of the Primary, Secondary, and Tertiarty elements if all three exist. If the term has no Tertiary element, the tail consists of the Primary and Secondary elements. If the term has no Secondary element, the tail is just the Primary element. Some higher level terms have no Primary element, but still have a leaf term which is the Sub Class or Class element. In those cases, the tail is the leaf term.

Translation from Nomenclature to Common Vocabulary

The CVT replaces the higher levels (Category, Class, and Sub Class) of the Nomenclature hierarchy with the top-level terms that the Common Vocabulary vocabulary uses for the Digital Archive. The top-level Common Vocabulary terms for the Digital Archive Type field are:

  • Document
  • Image
  • Map
  • Object
  • Publication

As shown earlier, the CVT translates:

Category 08: Communication Objects
    Documentary Objects
        Graphic Documents


Image, Photograph, Negative

It does this by following rules that tell the CVT to replace Category 08: Communication Objects, Documentary Objects, Graphic Documents with Image and then append the tail which is Photograph, Negative. The next section explains rules.

  • Common Term
  • Local Term that replaces a Common Term locally
  • Local Term that does not replace a Common Term

Most terms have four levels or less Only 5% have five levels None have six levels