Understanding the Vocabulary
MEDLINE uses a controlled vocabulary, meaning that there is a specific set of terms used to describe each article. Familiarity with this vocabulary will make you a better PubMed searcher.
The Medical Subject Headings (MeSH®)
MeSH is the acronym for "Medical Subject Headings." MeSH is the authority list of the vocabulary terms used for subject analysis of biomedical literature at NLM. MeSH vocabulary is used for indexing journal articles for MEDLINE and is also used for cataloging books and audiovisuals.
The MeSH controlled vocabulary is a distinctive feature of MEDLINE. It imposes uniformity and consistency to the indexing of biomedical literature. MeSH terms are arranged in a hierarchical categorized manner called MeSH Tree Structures and are updated annually.