Stop words are words that some users leave out of an index. By dropping stop words from an index, the index size can typically be reduced by as much as 30% for a word level index. A stop word typically is a word which doesn't contain much "informational"content. For example, some example stop words are: "and", "the", "of", "it", "as", etc.
ixCreateStopWordList returns an object which is used to match words against a stopword list. ixAddStopWord is used to add a word to the stop word list and ixIsStopWord is used to test to see if a word is a stop word.