In order that medical informaticians can create Open Systems for health care, they need to have a common language. Efforts in the 1980s at the National Library of Medicine to create a Medical Informatics Vocabulary (MIVoc) have been useful for document indexing purposes, but need to be continued and extended. The Committee of European Normalization Technical Committee 251 has created a project team for MIVoc, and that team has used both automatic and manual methods and referenced many sources in producing a vocabulary that has support from numerous experts in Europe.

MIVoc has both a glossary and a tree structure. The glossary has about 250 terms with detailed definitions that include various explanations and pointers. One critical pointer is the semantic link to other terms in MIVoc from a which a tree-structure is inferred. The success of MIVoc clearly depends on its being used, which in the long run depends also on the vocabulary being maintained.