What is a thesaurus?

A thesaurus is a systematic list of keywords that shows relationships between keywords. Examples are the MeSH (Medical Subject Headings) in PubMed and the Sociological Index Terms in Sociological Abstracts. You can search for keywords in the thesaurus; that way you’ll know for sure that the keywords that you use to search correspond to the keywords of the relevant database.

An example is the keyword ‘Women’, which is a very common term. If you look up this word in the Sociological Abstracts thesaurus, you’ll see that this database has attached the keyword ‘females’ to articles about women. You will also right away see a number of narrower, more specific terms and a list of related terms, such as ‘mothers’ or ‘working women’. This can give you ideas for broadening—or limiting—your own research.

There is another way in which using the thesaurus can make searching easier. This works because the thesaurus is a hierarchical list with mutual connections between different keywords. For example, if you look up the keyword ‘Europe,’ you can also search for all the countries in Europe at the same time by ticking this word (‘Europe’) in the thesaurus.