Vocabularies — further information

BGS vocabularies are lists of standardised terms covering a range of geoscience topics.

Standardised sets of terms — also known as 'dictionaries' or 'controlled vocabularies' — within datasets reduces the ambiguity associated with data mark-up and also enables records to be interpreted by computers. These dictionaries, or controlled vocabularies, control the terms we use in describing, and supporting the description of, scientific and other observations. This also opens up more possibilities for the datasets to be used in computer-aided manipulation, distribution and long term reuse.

In certain areas, it is not always possible or agreeable for data providers to use the same terms. In such cases, controlled vocabularies can be used as a medium to which data centres can map their equivalent terms.

The BGS has a number of geoscience vocabularies:

  • Rock Classification Scheme
  • Lexicon of Named Rock Units
  • ages of geochronological intervals used to attribute feature:
    • lithology
    • lithostratigraphy
    • names of mapped rock units
    • names of maps

Vocabulary structure

Our controlled vocabularies, or dictionaries, generally contain the following information for each term as a minimum:

  • Code — a permanent identifier for the term, designed predominantly for computer storage rather than human readability
  • Translation — a concise text string representing the term in human-readable form where space is limited (a short concise description, suitable also for drop down lists of applications)
  • Description — a full description of what is meant by the term

Our vocabularies are version controlled and we keep a record of all changes.


  • BGS vocabularies are required to have the above information as the minimum for each term, but complex or specialised dictionaries especially in the area of geoscience may have extra attributes that help qualify the term.
  • The preferred attribute name of the permanent identifier is 'CODE', but certain dictionaries may contain software specific names. In all cases the attribute that constitutes the permanent identifier is defined.
  • The preferred attribute name for the full description is 'DESCRIPTION', but some dictionaries may contain software or context specific descriptive fields.