Boolean searching allows you to combine your keywords and related terms with operators, such as AND, OR, and NOT to find the most relevant results possible from your search.
OR is used to tell the database that you want it to find any or all of the terms it links. The results could have just one of the terms, or it could have both/all of the terms it links. Because it will search for any of the terms, rather than all, OR will expand your number of results. This makes OR especially useful when you are searching for similar words (synonyms). OR broadens your search, and is an important concept to remember when you do not retrieve enough items in your search results. For example: social media OR Facebook OR Twitter