What is Boolean searching?
Last Updated: Jul 07, 2025    Views: 2

The library search can be very exacting about the search terms you need to use to get the results you want. For best results when searching, it's often best to start with a few basic search terms and add narrower terms after you see the results. In general, be sure that every word in the search bar is one that you need every result to have.

Fortunately, Boolean searching allows you to create a more precise search string using basic computer logic. When you are using an Advanced Search, Boolean operators will often appear to the left of each additional row of search boxes in a drop-down menu. However, you can also manually add Boolean operators to a simple search by typing them in all caps to distinguish them from regular search terms.

The most popular Boolean operators are AND, OR, and NOT. Each one tells the search engine what to do with the search term that comes after it.

AND

Example: cats AND dogs = Your search results will only include resources that mention both cats and dogs in the record. Using AND will narrow your results to fewer articles.

You can include the AND operator between every word in your search, but in most modern search engines, every word is already separated by an invisible AND by default, unless you specify otherwise. For example, these two searches should bring back very similar results: 

social media
social AND media

OR

Example: cats OR dogs = Your search results will include any resources that mention cats in the record, as well as any resources that mention dogs or both cats and dogs. Using OR will broaden your results.

OR is a great operator to use for finding a few different synonyms in the same search. If you want to use a more complex search string, put your OR items in parentheses. This will make sure the search is being parsed correctly:

stress AND (teens OR adolescents)

NOT

Example: cats NOT dogs = Your search results will include articles that mention cats in the record, but leave out any articles that also mention dogs. Using NOT will narrow your results to fewer articles.

NOT is a great operator to use if you are looking for a word that is often used in multiple contexts, but want to filter out the results that aren't relevant to you.

mouse NOT computer
twilight NOT (film OR movie OR book OR novel)

 

Boolean operators

Different databases and search engines may use different operators. For example, Google uses the minus sign (-) instead of NOT. Visit the page on Performing Basic Searches in Primo VE to find more information about using Boolean operators in the library OneSearch.