Definition of cetane in US English:



  • A colorless liquid hydrocarbon of the alkane series, used as a solvent.

    Alternative name: n-hexadecane; chemical formula: C₁₆H₃₄

    • ‘The secret formula behind the new diesel relies upon an increase in cetane; the equivalent of octane used in petrol.’
    • ‘Its density, viscosity, cetane index, combustion point, and several other parameters they looked at compare favorably with those of ethyl esters of sunflower, rape, groundnut, and soybean oils.’
    • ‘The composition may optionally also contain pour point depressants, cetane improvers, carbon-containing compounds which react with water, and/or emulsifiers.’
    • ‘Ultimate diesel has a guaranteed cetane rating of 55, compared with regular diesel at 51, and BP claims that it can reduce the noise and smoke in a diesel vehicle by up to 30 percent.’


Late 19th century: from Latin cetus ‘whale’, from Greek kētos (because related compounds were first derived from spermaceti) + -ane.