Definition of octane number in English:

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octane number

Pronunciation: /ˈäkˌtān ˌnəmbər/
(also octane rating)


A figure indicating the antiknock properties of a fuel, based on a comparison with a mixture of isooctane and heptane.
Example sentences
  • In particular, the formation of branched alkanes increases the octane number and combustibility of the resulting hydrocarbon.
  • Using a fuel of a higher octane rating than that recommended for your car doesn't improve its performance.
  • The higher the octane number you see on a gas pump, the more the fuel can be compressed before it explodes.

For editors and proofreaders

Syllabification: oc·tane num·ber

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