Define Boolean Operator

Search engines such as Google use Boolean operators to retrieve meaningful results.

Boolean operators are commands used in search engines to combine words or phrases in a way that produces useful results. Boolean logic was developed by English mathematician George Boole in the mid-nineteenth century.

AND

The word AND narrows a search by retrieving documents that contain all keywords listed. A search for "cake" AND "pie" returns only those documents that contain both words. The more keywords you enter, the fewer results you will receive.

OR

The word OR retrieves documents containing any of the keywords listed. A search for "candy" OR "chocolate" returns documents that contain the words "candy" or "chocolate" or both. The more keywords you enter, the more results you will retrieve.

NOT

The terms NOT or AND NOT exclude results. A search for "jaguar" AND NOT "car" returns documents pertaining to the big cat, but not to the luxury automobile.

Symbols

Many search engines recognize the plus (+) and minus (-) signs as Boolean operators. A plus sign is the same as the AND command and a minus sign is the same as NOT.

Phrases

Some search engines spell out Boolean logic. The phrase "any of the words" is the same as OR. The phrase "must not contain" means NOT.

References

• University of South Carolina: Searching with Boolean logic and proximity operators
• University of Nevada, Reno: Using AND, OR, and NOT (Boolean Operators)
• Delft University of Technology: Glossary

Resources

• Pandia.com: Boolean searching -- the operators AND, AND NOT, OR