octane
n. C / Un. a number that shows how well fuel burns in a car engine. A higher number usually means the fuel is better for high-performance cars.
n. a figure indicating the anti-knock properties of a fuel, based on the percentage of iso-octane in a reference mixture. Often used metaphorically to describe the intensity or power of an activity.
Most cars run perfectly well on standard octane fuel.
The mechanic recommended using a higher octane gasoline to prevent the engine from making a knocking sound.
The film's high-octane action sequences left the audience breathless, though critics argued the plot lacked the intellectual depth found in the director's earlier, more contemplative works.
From oct- + -ane.
Uncountable when referring to the chemical property; countable when referring to specific fuel grades.