1. Plural of isooctane; any of several isomeric forms of octane (a hydrocarbon with eight carbon atoms), especially 2,2,4-trimethylpentane, used as a reference standard in measuring gasoline octane ratings.
Usage: technical; chemistry; petroleum industry

Examples

• Isooctanes are important components in the formulation of high-octane gasoline.
• The octane rating scale is based on the performance of isooctanes compared to heptane.
• Refineries produce various isooctanes to improve fuel quality and engine performance.
• 2,2,4-trimethylpentane is the most common isooctane used in fuel standards.
• Different isooctanes have varying combustion characteristics in internal combustion engines.