The original wording of this principle (given below) and content of this page is scheduled to be reviewed. Improved wording will be posted as it becomes available.


For full details, see this paper:

Briefly, some important things to remember:

  • use rdfs:label for the primary label
  • include exactly one rdfs:label for every declared entity (e.g. class, property)
  • write labels, synonyms, etc as if writing in plain English text. ie use spaces to separate words, only capitalize proper names (e.g. Parkinson disease). Do not use CamelCase, do_not_use_underscores
  • spell out abbreviations. Abbreviations can be included as a separate property.
  • make the primary labels to be as unambiguous as possible. Remember, your ontology may be used in a different context than that for which it was originally intended. Remember also of course that the label should be unambiguous without looking at parent terms
  • labels should be unique within an ontology
  • use the IAO property ‘obo foundry unique label’ to declare a pan-OBO unique label if required

Date Accepted

  • 2009


Started as internal policy during Daniel Schobers ph.D thesis, was continued and published at EMBL-EBI, and is now refined and amended at IMBI UMC Freiburg.