Query expansion
<information science> Adding search terms to a user's search.
Query expansion is the process of a
search engine adding search terms to a user's
weighted search.
The intent is to improve
precision and/or recall.
The additional terms may be taken from a thesaurus.
For example a search for "car" may be expanded to: car cars auto autos automobile automobiles.
The additional terms may also be taken from documents that the user has specified as being relevant; this is the basis for the "more like this" feature of some search engines.
The extra terms can have positive or negative weights.
