In the electrochemical series, the electrodes are arranged in the increasing order of their reduction potential under standard conditions of 1M electrolyte concentration, 298 K temperature, and 1 bar atmospheric pressure.
It is also known as the activity series as the activities of two different electrodes towards displacement reaction are compared; whether the electrode under standard reaction condition will have reduction potential or oxidation potential.
As the electrochemical series are expressed as a reduction-oxidation equilibrium reaction, the reverse order will be seen if you arrange the electrodes per their standard oxidation potential.
Read more about the electrochemical series and its significance.