The Rosetta Stone as a metaphor for classification and vocabulary challenges in health care provides important insight into our current dilemma. The Stone, discovered by one of Napoleon's officers invading Egypt in 1799, unlocked the meanings behind the ancient language of Egypt (http://tqd.advanced.org/3011/egypt1.htm). Up until the Rosetta Stone was discovered, three distinct and untranslatable languages comprised the ancient Egyptian language: Egyptian Hieroglyphs, Demotic, and Greek. The Stone enabled the ancient language to be decoded because it contained three inscriptions of specific terms and concepts across the three different scripts.

In nursing and health care the development of terminology and vocabularies has occurred via disciplinary knowledge development, and without a "Rosetta Stone," or system to link various vocabularies. Vocabularies have evolved within disciplines, specialties, and settings; yet a system is needed to cross and link the terms used in health care.

The equivalent to the Rosetta Stone in the U.S. is the Unified Medical Language System (UMLS). The UMLS is a long-term research and development effort being conducted through and coordinated by the National Library of Medicine (NLM), designed to facilitate the retrieval and integration of vocabularies and information from multiple machine-readable biomedical sources. The UMLS retrieves information from numerous sources, including bibliographic material, clinical records, databanks, data repositories, knowledge-based systems, and directories. The major barrier to effective retrieval has been the use of multiple vocabularies and classifications used by different health professionals in the US.

The UMLS electronically links vocabularies and classification systems through a system of four knowledge sources (http://www.nlm.nih.gov/pubs/factsheets/umls.html): Metathesaurus, Semantic Network, Specialist Lexicon, and Information Sources Map. The Metathesaurus is organized by concept or meaning, and contains semantic information on approximately 476,322 biomedical and related concepts with 1,051,903 different names. The Metathesaurus contains vocabulary terms, classifications, coding systems, and thesauri developed and maintained by various professional organizations, such as the American Nurses Association, and identifies alternate names for the same concept and relationships between different concepts.

The Specialist Lexicon contains syntactic information about health care-related terms and concept names from the Metathesaurus, as well as other non-health related English words used in communication that are not necessarily included in the scope of the Metathesaurus. The Semantic Network is comprised of a network of general categories or classifications which consistently categorize all concepts from the Metathesaurus, and identifies allowable relationships between terms. The Information Sources Map contains information on the available sources of the machine-readable health related information. Each term or concept is defined and cross-mapped to terms or concepts within other classification systems or vocabularies.

All vocabularies and classifications for nursing that have been approved by the American Nurses Association are incorporated into the UMLS. These nursing vocabularies and classifications in UMLS can be extrapolated, resulting in what could be described as a Unified Nursing Language System (UNLS) (McCormick, et al, 1994; McCormick & Zielstorff, 1995). This UNLS, when extrapolated, could be tested against large scale nursing data repositories to determine if it is also representative of vocabularies such as acute care, primary care, long-term care, outpatient, community, school health nursing, occupational health, and the many realms where nursing care is delivered.