What you mean by octane number?

Question

Octaine term conected with rating of automotive fuil.

Answer 1

Gas is made in different "grades" of octane. The higher the octane rating the more power that gas will give your car and the less chance your car will have for premature ignition and other problems. High grade just isn't necessary or even worth the expense in any but the most high performance cars sold, like a Lamborghini etc...

Answer 2

has to do with how efficiant it burns... higher the number the better