Petroleum

Petroleum is a natural resource made up of a mixture of hydrocarbons. It exists in different forms: liquid (crude oil), gas (natural gas), or solid (bitumen). While people often think of petroleum as crude oil, it also includes natural gas and thick, sticky bitumen found in tar sands.

• The liquid and gas forms of petroleum are closely linked, so the term "petroleum" is often used to refer to both crude oil and natural gas.
• The word “petroleum” means “rock oil” in Latin, coming from petra (rock) and oleum (oil). Although some claim that Avicenna, a Persian scientist, used it about 500 years earlier, Georgius Agricola popularised it first in 1556.