That would be the Hawker 800XP wouldn't it?
I've got one (of many!!) manuals open and funnily enough, it's not defined. (Hawker 800XP Pro Line 21 AFM, Section 6 W&B) (Flight Safety)
Nearest I can find is Minimum Operating Weight - The minimum weight as which the gust criteria for structural integrity has been shown.
I'll have a look at the manuals CAE gave us, if that does not answer it, I'll "phone a friend".
