Standard Deviation Statistic Question

In regards to the standard deviation statistic present in the "Winnings Summary" report,

Over a period of 80K hands, I am running at -1 bb/100 with an EV of +1.5 bb/100.

The value in the Standard Deviation column is 68.64

Can you provide me with a detailed description of how this value is calculated and what information it is providing me?

I am having severe difficulty translating a wikipedia definition into poker related terms. Thank you in advance for your help.