The meaning and definition of All or None AON -
A stipulation applied to a buy or sell order which instructs the broker to fill the order completely or not to fill it at all. All or None orders are typically associated with large trades; investors use the restriction to prevent an order from being filled incrementally - a process which can result in payment of multiple commissions. An important distinction about AON orders is that if the trade cannot be executed it is not automatically cancelled - as it would be if the order was marked fill or kill (FOK).