Boolean Search: a Boolean search is a search engine query that utilizes Boolean logic. In this algebraic operation, a formula is used to describe logical situations in the same way that others describe numeric equations. Introduced by George Boole in his book The Mathematical Analysis of Logic in 1847, Boolean logic is now used in a variety of ways in the fields of digital electronics, programming, set theory and statistics.

Most search engines allow users to perform Boolean searches and other mathematical formulas to find relevant information. These formulas use keywords and logical terms such as AND, OR, or NOT. For example, a Boolean search for a water bottle might read "blue AND aluminum AND water bottle." Instead of words, however, search engines like Google will use symbols instead of words: a minus sign will be used to represent NOT, while a blank space will be interpreted as AND. Accordingly, most search engines include the logical term AND with a user's query by default, which requires results to be relevant for all of the words in a query. This allows users to type in a search query that is more conversational and natural, like "blue aluminum water bottle."