<information science> A search based on frequencies of the
search terms in the documents being searched. Weighted
search is often used by search engines. It produces a
numerical score for each possible document. A document's
score depends on the frequency of each search term in that
document compared with the overall frequency of that term in
the entire corpus of documents. A common approach is called
tf.idf which stands for term frequency * inverse document
frequency. Term frequency means "the more often a term occurs
in a document, the more important it is in describing that
document."
http://ciir.cs.umass.edu/cmpsci646/ir4/tsld034.htm Inverse
document frequency means the more documents a term appears in,
the less important the term is.
A simple weighted search is just a list of search terms,
for example: car automobile
Weighted search is often contrasted with boolean search.
It is possible to have a search that syntactically is a
boolean search but which also does a weighted search.
See also query expansion.
For a detailed technical discussion see Chapter 5,
"Search Strategies", in the reference below.
