A noise word is a word such as the or if that is so common that it is not useful in searches. To save time, noise words are not indexed and are ignored in index searches. To modify the list of words defined as noise words, click Options > Preferences > Letters and Words, and click the Edit button next to the noise word list name.
The words in the noise word list do not have to be in any particular order, and can include wildcard characters such as * and ?. However, noise words may not begin with wildcard characters.
When you create an index, the index will store its own copy of the noise word list. Changes you make to the noise word list will be reflected in future indexes you create but will not affect existing indexes.