octane number (also `octane rating)

measure of the efficiency and quality of a petrol in comparison with those of a fuel taken as standard (the highest number indicating the highest quality) 辛烷值.

occupied, occupier, occupy, occur, occur to, occurrence, ocean, ocean lane, ocean-going, oceanarium, Oceania, oceanic, oceanography, ocelot, ochre (US also ocher), Oct, oct(o)-, octagon, octagonal, octane, octave, octavo, octet (also octette), October, octogenarian, octopus, ocular, oculist, odd, odd job man, odd jobs, odd-looking, oddball, oddity, oddly, oddment, oddness, odds, odds-on, ode,