All or None (AON) Order
At E*TRADE Canada, an AON order is an order (day or GTC) to buy or sell all the shares of a certain security that are covered by the order at the best price available at the time the order is executed, or not at all. Although by definition, the AON order avoids partial executions which could occur at different prices and generate additional commission charges as well, it has to be used with care because if there is not enough stock available, you may end up not owning the stock at all. AON orders receive the lowest priority for execution.