In plain English
What Stop order means
A stop order is triggered by price. Once the market trades at or through the stop price, the order is activated. In many retail and exchange settings, that means it then seeks execution at the best available price, which may differ from the trigger level.
Why it matters
Stop orders are commonly used to enter breakouts or to exit losing trades automatically. The key point is that a stop price is a trigger, not a guaranteed execution price, so the fill can be worse than the stop level in a fast or gapping market.
Example
If you place a buy stop at 1.0900 in EUR/USD, the order becomes active when price reaches 1.0900. If the market jumps to 1.0904 before it can fill, the execution may occur near 1.0904 instead of exactly at 1.0900.
Quick answers
Common questions
Is a stop order the same as a stop-loss order?+
No. A stop-loss order is a stop order used to close an existing position and limit losses.
Does a stop order guarantee execution at the stop price?+
No. The stop price is the trigger; the actual execution price can be worse.
Sources