Produces search results with either or both of your keywords. Example: extraterrestrials OR aliens Using the OR operator will expand your search because it will tell the search engine to produce results that have either or both terms. The OR operator is useful when you are trying to find instances of similar words. A person doing research on aliens may very well be interested in extraterrestrials as well. In the diagram below the area of the circles represents the number of hits your keywords will produce. Using the OR operator allows the search engine to produce results that have either term or both terms. As a result, both circles are fully shaded and it is likely that this kind of search will produce quite a few hits.