Query expansion in PostgreSQL

Question

I've just read in PostgreSQL manual that it provide full-text search functions including parsing, indexing and searching on documents text.
My question is: it is possible to obtain a query expansion mechanism using a thesauri (or a dictionary)? I do not try these function yet...but it seems that a single lexeme is substited by another single lexeme. Is it possible to add to the query lexemes that are synonims of the lexemes originally in the query?

Answer 1

I've never used it but yes, there seems to be a thesaurus dictionary that may do what you want:

http://www.postgresql.org/docs/9.0/static/textsearch-dictionaries.html#TEXTSEARCH-THESAURUS