What is Buy Limit order?

It is pending order, which means to buy when the ask price gets equal to the specified value. Herewith, the current price is higher than the value of the set order. Typically, the orders of this type are set in reliance on the assumption that the instrument price, having declined to a certain level, will stop its fall and start to grow. It is impossible to set buy limit orders above the current ask price, you have to use buy stop orders for this.