The CCDB dictionary provides definitions for terms and concepts used in the CCDB. Where possible, the CCDB maps these concepts to unique identifiers contained in the Unified Medical Language System (UMLS) or other appropriate ontologies. Identifiers beginning with "BF" refer to the Bonfire, a collection of knowledge sources developed and maintained by the Biomedical Informatics Research Network (BIRN) project. More information about Bonfire IDs can be found here.