A container for storing gasoline used in the United States; red containers are typically used. Gasoline (gas) or petroleum spirit (petrol) is a petroleum-derived liquid mixture consisting mostly of aliphatic hydrocarbons, enhanced with iso-octane or the aromatic hydrocarbons toluene and benzene to increase its octane rating, and is primarily used as fuel in internal combustion engines. Most Commonwealth countries or former Commonwealth countries (with the exception of Canada) use the term "petrol" (abbreviated from petroleum spirit). The term "gasoline" is commonly used in North America where it is often shortened in colloquial usage to "gas." This should be distinguished in usage from genuinely gaseous fuels used in internal combustion engines such as liquefied petroleum gas (which is stored pressurised as a liquid but is allowed to return naturally to a gaseous state before combustion). The term mogas, short for motor gasoline, distinguishes automobile fuel from aviation gasoline, or avgas. The word "gasoline" can also be used in British English to refer to a different petroleum derivative historically used in lamps, but this use is now uncommon.