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.’
    • ‘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.’
    • ‘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.’


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