Nitro is simply something that we use in model engines for a bit more power and smoother running. Drag racers use a lot of it for a lot of power.
They use almost 100% nitro in those engines and methanol is the additive, the term Nitro is correct for those engines. Dar is correct, did we call the gasoline engines of the past Lead engines because the fuel had lead in it? I often ignore any posts that refer our engines and planes as Nitro.