Both Buy and Sell Stop Orders are trade order set before current price hits those orders and gets you into a new trade.
Buy Stop Order:
An order that is executed at a specific predetermined price that is above the current price.
Sell Stop Order:
An order that is executed at a specific predetermined price that is below the current price.
NEVER chases price when making a Forex trade, let price action come to your entry by setting either a Buy or Sell stop order. Then make sure you set your stop loss and targets at that time too.