A process run by search engines to group together commonly associated words in a document to answer a search query. LSI assigns value to content words in the document that are relevant to the theme or topic. LSI does not require exact keyword searches in order to provide relevant results, even if the document does not contain any of the searched keywords at all.
For example, searching a sports database for Perth Wildcats player Jesse Wagstaff may return results for team news, upcoming games and previous basketball championships without containing his name at all. LSI is intelligent enough to guess that “Jesse Wagstaff” is closely related to these results.