All-or-None Order

Definition: An order type that only executes when the full amount of the shares in the order can be executed, otherwise the order doesn’t execute at all.  In other words, this order type guarantees there are no partial fills.
Example:  If you place a Market Buy order for 100 shares of Google (GOOG) and there are only 75 available at the time the order is placed, then the order would not be executed. The order would wait until there were 100 shares available to purchase and then execute at that price.