Kerosene, also known as paraffin, is a combustible hydrocarbon liquid derived from petroleum. It is a low-viscosity, clear liquid formed from hydrocarbons obtained from the fractional distillation of petroleum between 150 and 275 °C (300 and 525 °F), resulting in a mixture with a density of 0.78–0.81 g/cm3. Kerosene is composed of hydrocarbon molecules that typically contain between 6 and 20 carbon atoms per molecule, predominantly containing 9 to 16 carbon atoms.

Kerosene is widely used as a fuel in aviation as well as households. It is used to power jet engines of aircraft (jet fuel), as well as some rocket engines in a highly refined form called RP-1. Kerosene is also commonly used as a cooking and lighting fuel, and for fire toys such as poi. In parts of Asia, kerosene is sometimes used as fuel for small outboard motors or even motorcycles. Kerosene is a major component of aviation fuel, making up more than 60% of the fuel.

Kerosene is a versatile fuel that can be used for many applications. Its uses vary dramatically from fuel for oil lamps to cleaning agents, jet fuel, heating oil, or fuel for cooking. Kerosene is also used as an oil in central heating systems and can be used as a cleaning agent. In less-developed countries, kerosene is an important source of energy for cooking and lighting.

Kerosene is a complex mixture of paraffins, naphthenes, and aromatic hydrocarbons. Its chemical composition depends on its source, but it usually consists of about 10 different hydrocarbons, each containing 10 to 16 carbon atoms per molecule. Kerosene is less volatile than gasoline and tends to contain hydrocarbons that have anywhere from 11 to 13 carbons in the chains.

In summary, kerosene is a flammable liquid derived from petroleum that is widely used as a fuel in aviation and households, as well as for cooking, lighting, and cleaning.