medical subject headings Medical Subject Headings (MeSH) is a comprehensive controlled vocabulary for the purpose of indexing journal articles and books in the life sciences; it can also serve as a thesaurus that facilitates searching. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed article database and by NLM's catalog of book holdings. MeSH can be browsed and downloaded free of charge on the Internet through PubMed. The yearly printed version was discontinued in 2007 and MeSH is now available online only. Originally in English, MeSH has been translated into numerous other languages and allows retrieval of documents from different languages. (Excerpt from Wikipedia article: Medical Subject Headings (MeSH)) 11 12 0.6 http://www.ariadne.ac.uk/sites/all/datacharts/hc/1384-chart-wp.html subject heading An index term, subject term, subject heading, or descriptor, in information retrieval, is a term that captures the essence of the topic of a document. Index terms make up a controlled vocabulary for use in bibliographic records. They are an integral part of bibliographic control, which is the function by which libraries collect, organize and disseminate documents. They are used as keywords to retrieve documents in an information system, for instance, a catalog or a search engine. A popular form of keywords on the web are tags which are directly visible and can be assigned by non-experts also. Index terms can consist of a word, phrase, or alphanumerical term. They are created by analyzing the document either manually with subject indexing or automatically with automatic indexing or more sophisticated methods of keyword extraction. Index terms can either come from a controlled vocabulary or be freely assigned. (Excerpt from Wikipedia article: subject heading) 13 18 0.8 http://www.ariadne.ac.uk/sites/all/datacharts/hc/1907-chart-wp.html