isooctane[ī′sō äk′tān, -sə-]
a liquid hydrocarbon, (CH)CHCHC(CH), used with normal heptane to prepare antiknock rating standards and arbitrarily assigned an octane rating of 100
Origin of isooctaneiso- + octane
A flammable liquid hydrocarbon, C8H18, having a highly branched structure and used as a solvent and to determine the octane ratings of fuels.
(countable and uncountable, plural isooctanes)