Petrol is a transparent, petroleum-derived liquid that is used primarily as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain ethanol as an alternative fuel. In North America, the term gasoline is often shortened in colloquial usage to gas, but some people use the term petrol, which is the common name in the UK and elsewhere in the Commonwealth of Nations. Under normal ambient conditions, its material state is liquid, unlike liquefied petroleum gas or natural gas.