"This is the list of subject headings that may be useful for disaster and all-hazards preparedness and response topics. [...] MeSH [Medical Subject Headings] is the National Library of Medicine's (NLM) controlled vocabulary thesaurus of descriptors in a hierarchical structure that aid searching at various levels of specificity. The MeSH thesaurus is used by NLM for indexing articles for the MEDLINE/PubMed® database. MeSH terms provide a consistent way to retrieve information that may use different terminology for the same concepts."
National Library of Medicine (U.S.). Specialized Information Services Division: http://sis.nlm.nih.gov/