柯林斯詞典octane number (also octane rating) 1. N a measure of the quality of a petrol expressed as the percentage of isooctane in a mixture of isooctane and n-heptane that gives a fuel with the same antiknock qualities as the given petrol 辛烷值 返回 octane number劍橋詞典a number showing the quality of petrol by representing how well and with how much power it can make an engine work 辛烷值 返回 octane number