octane scale

octane scale

[′äk‚tān ‚skāl] (engineering) Series of arbitrary numbers from 0 to 120.3 used to rate the octane number of a gasoline; n-heptane is 0 octane, isooctane is 100, and isooctane + 6 milliliters TEL (tetraethyllead) is 120.3.