A royal flush in which the cards appear in numerical order. Some video poker games pay a bonus for a Sequential Royal Flush-- and for some of these the order (ascending or descending) might matter.
A reduction in a pay out from the typical payout or maximum payout for a particular hand or game. Casinos often short some commonly occurring payouts and raise other rare payouts (ex, Royal Flush). This generally reduces the EV for the entire game.