It's outdated shorthand for a half-reaction, exactly as Vihsadas and Kaustikos pointed out. It goes along with cell shorthand. For an electrochemical cell, they often use shorthand such as:
Zn|0.10 M Zn2+||0.10 M Cu2+|Cu
I assume such a thing is present in your review materials because the author wants to expose you to as many different ways to present the material as possible.
You really need to be careful in terms of terminology, because the MCAT preys on careless errors. The standard reduction potential is for a reduction HALF-reaction. It is measured as a voltage and can be referred to as an emf in terms of voltage. But it is only a half-reaction.
What you have typed is a standard reaction potential. Ereaction = Ereduction + Eoxidation is for a full redox reaction. It's a subtle difference, but one that you can be sure an incorrect answer is based on.