An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is both hydrophobic (does not mix with water, literally "water fearing") and lipophilic (mixes with other oils, literally "fat loving"). Oils are usually flammable and surface active. Most oils are unsaturated lipids that are liquid at room temperature.

The general definition of oil includes classes of chemical compounds that may be otherwise unrelated in structure, properties, and uses. Oils may be animal, vegetable, or petrochemical in origin, and may be volatile or non-volatile. They are used for food (e.g., olive oil), fuel (e.g., heating oil), medical purposes (e.g., mineral oil), lubrication (e.g. motor oil), and the manufacture of many types of paints, plastics, and other materials. Specially prepared oils are used in some religious ceremonies and rituals as purifying agents.

Phillips Petroleum Company was an American oil company incorporated in 1917 that expanded into petroleum refining, marketing and transportation, natural gas gathering and the chemicals sectors. It was Phillips Petroleum that first found oil in the North Sea on December 23, 1969, at a position that was later named Ekofisk.On August 30, 2002, Conoco Inc. merged with Phillips Petroleum to form ConocoPhillips, becoming the third largest integrated energy company and second-largest refining company in the United States. The company moved its headquarters to Houston.In 2012, ConocoPhillips split into two separate companies. The legacy company kept its name, and spun off the midstream and downstream portions of its business. The new company, which owns the refinery, chemical and pipeline assets formerly held in ConocoPhillips, is named Phillips 66, the brand name and trademark used by the original Phillips Petroleum from 1930 until the 2002 ConocoPhillips merger.