MeSH (Medical Subject Headings) terms provide a controlled vocabulary for indexing articles in PubMed. There are two ways to connect to MeSH terms from the PubMed homepage. Users can search for a term like "double vision" in the MeSH database to find the appropriate MeSH term. Once the correct MeSH term is identified, it can be added to a PubMed search to retrieve relevant articles that have been indexed with that term.