Octane is actually a form of isomer with many variations of branching carbon chains with regards to amounts and locations error. That doesn’t seem right.
The term octane, as we know it, was made popular by fuel companies in the 60s. Since then it has become synonymous with describing the performance of what fuel can offer you.
What we are familiar with is in regards to a fuel ability to retard knock, or stop pre-ignition, inside of an engine. This due to the heat caused by the compression of gases within the cylinder. Basically, the octane rating of gasoline indicates how much the fuel in the air/fuel mixture can be compressed before it spontaneously combusts. Ideally we want that spontaneous combustion point to be right at TDC (Top Dead Center) or ATDC (point right After Top Dead Center) of the cylinder cycle, which is also where our spark plug would be igniting. This would be maximum efficiency.
So in theory we are trying to optimize your octane level to exactly what your engine is requiring. Now depending on your vehicle at its current compression you may or may not need high-octane fuels. Often enough vehicles are mapped or tuned in order to safely operate with whatever fuel can be found at a local gas station or marina. However, if you are interested in getting more horsepower, protecting your engine from some of the gaps created with ethanol and other alcohol additives, a reliable octane additive is what the doctor ordered!