English Noun cetane number (plural cetane numbers) A performance rating of diesel fuel corresponding to the percentage of cetane in a mixture with isocetane (or, formerly, methylnaphthalene) that would have the same performance. Translations performance rating of diesel fuel French: indice de cétane m Persian: عدد ستان ('adad-e setân) See also octane number Wikiwand - on Seamless Wikipedia browsing. On steroids.