[3] Enterprise search systems also use access controls to enforce a security policy on their users.
These may include stemming, lemmatization, synonym expansion, entity extraction, part of speech tagging.
The index may contain the dictionary of all unique words in the corpus as well as information about ranking and term frequency.
The query consists of any terms the user enters as well as navigational actions such as faceting and paging information.
The processed query is then compared to the stored index, and the search system returns results (or "hits") referencing source documents that match.