According to
http://java.sun.com/j2ee/1.4/docs/tutorial/doc/JAXPXSLT.html :
"[Xalan] is said to be the name of a rare musical instrument, but the
only instrument that comes close is the Xalam ("zah-LAHM") -- an early
precursor to the banjo."

For which see http://en.wikipedia.org/wiki/Xalam .

-Jason Cho