Here are links to defintions if it helps: <A HREF="http://www.anz.com/edna/dictionary.asp?action=content&content=delta-neutral" target="_new">http://www.anz.com/edna/dictionary.asp?action=content&content=delta-neutral</A> <A HREF="http://www.anz.com/edna/dictionary.asp?action=content&content=delta_hedging" target="_new">http://www.anz.com/edna/dictionary.asp?action=content&content=delta_hedging</A> Basically, trying to match first derivative with respect to price change over some price interval.