limit order is an order to buy at market below the current market price or to sell at market above the current price if the order price is reached. This is used when the trader thinks that the price action will reverse upon hitting that specified price level.
A Stop order|stop order is an order to buy at market above the current market price or to sell at market below the current price if the order price is reached. This is used when the trader thinks that the price action will continue upon reaching that specified price level.