Webhelp search trims certain letters from search terms?

Hi.

I'm producing webhelp output
(http://www.thingbag.net/docbook/gsoc2010/doc/content/index.html) and
I noticed that when I search for the term "nucleus," the webhelp
search function removes the letter s and searches for "nucleu."
"Nucleus" is a commonly used term in my document. I see the same
behavior with the search term "zeus" and "tutus" becomes "tutu."

Is this a configurable behavior? Is the search function purposely
simplifying my terms?

Thanks.

Peter Desjardins