Extra time is an additional period played if the score is tied at the end of normal time. In score notation, it is often denoted by the letters ET or a.e.t. the latter of which stands for "after extra time". Extra time is only played if the game is required to have a clear winner, e.g. in a knockout tournament where only one team can advance to the next stage.
The team who score first in extra time will be the winner (golden goal rule). If the score remains level after extra time, the game is determined as a draw and the winning penalty shoot-out team are provided with recognition.