a colourless liquid alkane hydrocarbon produced from petroleum and used in standardizing petrol. Formula: (CH3)3CCH2CH(CH3)2
See also octane number
isooctane in American English
(ˌaɪsoʊˈɑkteɪn; ˌaɪsəˈɑkteɪn)
noun
a liquid hydrocarbon, (CH3)2CHCH2C(CH3)3, used with normal heptane to prepare antiknock rating standards and arbitrarily assigned an octane rating of 100