Stop words are words configured to be ignored by the MDEX Engine search query engine. A stop word list typically includes words that occur too frequently in the data to be useful (for example, the word bottle in a wine data set), as well as words that are too general (such as clothing in an apparel-only data set).

If the is marked as a stopword, then a query for the computer will match to text containing the word computer, but possibly missing the word the.

Stop words are not currently expanded by the stemming and thesaurus equivalence set. For example, suppose you mark item as a stopword and also include a thesaurus equivalence between the words item and items. This will not automatically mark the word items as a stopword; such expansions must be applied manually.

Stop words are respected when matching thesaurus entries to user queries. For example, suppose you define an equivalence between Muhammad Ali and Cassius Clay and also mark M as a stopword (it is not uncommon to mark all or most single letter words as stopwords). In this case, a query for Cassius M. Clay would match the thesaurus entry and return results for Muhammad Ali as expected.