Discretionary Order

A Discretionary order is an order type offered by certain exchanges. This order is a limit order submitted with a hidden, specified 'discretionary' amount off the limit price which may be used to increase the price range over which the limit order is eligible to execute. The market sees only the limit price.

A discretionary order is a conditional order placed with some latitude for execution. More broadly, a discretionary order is one where a broker or other financial markets professional can place and work an order without explicit acknowledgement from the customer. Discretionary orders help to improve the chances of order execution while still also allowing the investor to place certain conditional constraints. (Investopedia)