isooctane [ahy-soh-ok-teyn] Word Origin noun Chemistry.
- the octane C8H18, used as one of the standards in establishing the octane number of a fuel.
Compare octane number. Origin of isooctane First recorded in 1905–10; iso- + octane British Dictionary definitions for isooctane isooctane noun
- a colourless liquid alkane hydrocarbon produced from petroleum and used in standardizing petrol. Formula: (CH 3) 3 CCH 2 CH(CH 3) 2See also octane number