I checked in online, but my status is stand-by. What does it mean?

Your check-in has been completed, but the flight is full, and we were not able to assign you a seat at this moment. You will get your seat number at the check-in desk or at the departure gate in case if there are seats available. If we are not able to give you a seat on the flight, we will arrange a new routing for you and provide customer care during the waiting time.