Introduction
When it comes to entering keywords in a search, some search engines use a particular formula to read your command. One such format is the Boolean search.
The name Boolean comes from mathematician George Boole (1815-1964) who came up with a method to express specific queries. It is devised as a list of words or operators that link keywords together to help a search.
Not all search engines use Boolean operators, so again understanding how a couple of search engines work would be useful. Others automatically place these words invisibly into your search so that you do not have to. The main Boolean operators are AND, OR, NOT. They are always written in CAPITAL LETTERS.
AND: When you place AND between two words it tells the search engine that you want all of these words in the results page. For example: Galway AND Ireland, would bring up only the web pages containing Galway and Ireland.
OR: If you put OR between your keywords, you are telling the search engine to come back with results that will have either of your keywords or all. For example: cats or felines would retrieve pages that contain the word cats or felines or both.
You can increase your search further by using a combination of Operators. For example: (cats or felines) and dogs, would be telling the search engine to look for pages containing the words either cats or felines but had to include dogs.
NOT: By putting NOT in your search, you are asking the search engine to look up pages that contain one keyword but not the other. For example: recipes NOT desserts, is asking for web pages that contain recipes but not those for desserts.
You can also use the plus (+) and minus (-) signs between words, but without any spaces. For example, recipes-desserts. It will have the same results as before.
If you are looking for information on a particular subject but are unsure of how to phrase a keyword search, you can use a process known as ‘stemming’. For example, if you are looking for web sites on houses or housing, in the search box type hous*. This will bring up all the web pages containing house, houses, housing, etc. However, this does not work on Google.
