petroleum

n. dark oil composed of hydrocarbons, flammable fluid that is drilled from the Earth and refined to produce various types of fuel

Petroleum (Latin Petroleum derived from Greek πέτρα (Latin petra) - rock + έλαιον (Latin oleum) - oil) or crude oil is a naturally occurring liquid found in formations in the Earth consisting of a complex mixture of hydrocarbons (mostly alkanes) of various lengths. The approximate length range is C5H12 to C18H38. Any shorter hydrocarbons are considered natural gas or natural gas liquids, while long-chain hydrocarbons are more viscous, and the longest chains are paraffin wax. In its naturally occurring form, it may contain other nonmetallic elements such as sulfur, oxygen, and nitrogen. It is usually black or dark brown (although it may be yellowish or even greenish) but varies greatly in appearance, depending on its composition. Crude oil may also be found in semi-solid form mixed with sand, as in the Athabasca oil sands in Canada, where it may be referred to as crude bitumen.
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Petroleum /pe·tro·le·um/ a thick natural mixture of gaseous, liquid, and solid hydrocarbons obtained from beneath the surface of the earth. [more]Petroleum - Community and Resources

Noun
1. a dark oil consisting mainly of hydrocarbons
(synonym) crude oil, crude, rock oil, fossil oil
(hypernym) oil
(hyponym) residual oil, resid
(substance-meronym) carbon, C, atomic number 6

n. petroleum, oil, flammable fluid that is drilled from the Earth and refined to produce various types of fuel