AskDefine | Define oil

Dictionary Definition



1 a slippery or viscous liquid or liquefiable substance not miscible with water
2 oil paint used by an artist [syn: oil color]
3 any of a group of liquid edible fats that are obtained from plants [syn: vegetable oil]


1 cover with oil, as if by rubbing; "oil the wooden surface"
2 administer an oil or ointment to ; often in a religious ceremony of blessing [syn: anoint, inunct, anele, embrocate]

User Contributed Dictionary



  • , /ɔɪl/, /OIl/
  • Rhymes with: -ɔɪl


  1. Liquid fat.
  2. Petroleum-based liquid used as fuel or lubricant.


liquid fat
Petroleum-based liquid


lubricate with oil
to grease with oil for cooking




Extensive Definition

An oil is a substance that is in a viscous liquid state ("oily") at ambient temperatures or slightly warmer, and is both hydrophobic, (immiscible with water, lit. water fearing) and lipophilic (miscible with other oils, literally "fat loving"''). This general definition includes compound classes with otherwise unrelated chemical structures, properties, and uses, including vegetable oils, petrochemical oils, and volatile essential oils. Oil is a nonpolar substance.


Oil is a non-scientific term used to refer to certain diverse and unrelated compounds sharing the same physical properties (such as viscosity and a hydrophobic nature), while ignoring related compounds. The compounds found in cooking oil are chemically very similar, almost identical, to those found in butter and very different from those found in diesel fuel, but while diesel is an oil, butter is not. Indeed diesel is once again very similar to natural gas, but gas is certainly not oil. This disparity stems partly from the fact that oils must be liquid at room temperature, and thus only certain liquid chemicals in many unrelated families are recognised, collectively, as 'oil'. Scientists, instead of using the term 'oil', adopt the terms lipids and other terms to denote them instead.

Types of oils

Mineral oil

All oils, with their high carbon and hydrogen content, can be traced back to organic sources or space. Mineral oils, found in porous rocks underground, are no exception, as they were originally the organic material, such as dead plankton, accumulated on the seafloor in geologically ancient times. Through various geochemical processes this material was converted to mineral oil, or petroleum, and its components, such as kerosene, paraffin waxes, gasoline, diesel and such. These are classified as mineral oils as they do not have an organic origin on human timescales, and are instead derived from underground geologic locations, ranging from rocks, to underground traps, to sands.
Other oily substances can also be found in the environment, the most well-known being asphalt, occurring naturally underground or, where there are leaks, in tar pits .
Petroleum and other mineral oils, (specifically labelled as petrochemicals), have become such a crucial resource to human civilization in modern times they are often referred to by the ubiquitous term of 'oil' itself.

Organic oils

Oils are also produced by plants, animals and other organisms through organic processes, and these oils are remarkable in their diversity. Oil is a somewhat vague term to use chemically, and the scientific term for oils, fats, waxes, cholesterol and other oily substances found in living things and their secretions, is lipids.
Lipids, ranging from waxes to steroids, are somewhat hard to characterize, and are united in a group almost solely based on the fact that they all repel, or refuse to dissolve, in water, and are however comfortably miscible in other liquid lipids. They also have a high carbon and hydrogen content, and are considerably lacking in oxygen compared to other organic compounds and minerals.


Food oils

Many edible vegetable and animal oils, and also fats, are used for various in cooking and food preparation. In particular, many foods are fried in oil much hotter than boiling water. Oils are also used for flavoring and for modifying the texture of foods e.g Stir Fry.
Health advantages are claimed for a number of specific oils such as omega 3 oils (fish oil, flaxseed oil, etc) and evening primrose oil.
Trans fats, often produced by hydrogenating vegetable oils, are known to be harmful to health.


Almost all oils burn in air generating heat, which can be used directly, or converted into other forms of energy by various means, for example, heating water into steam which is funneled into a turbine which turns a huge magnet. This spins and generates electricity. Oils are used as fuels for heating, lighting (e.g. kerosene lamp), powering combustion engines, and other purposes. Oils used for this purpose nowadays are usually derived from petroleum, (fuel oil, diesel oil, petrol (gasoline), etc), though biological oils such as biodiesel are gaining market share.

Heat transport

Many oils have higher boiling points than water and are electrical insulators, making them useful for liquid cooling systems, especially where electricity is used.


Due to their non-polarity, oils do not easily adhere to other substances. This makes oil useful as lubricant for various engineering purposes. Mineral oils are more suitable than biological oils, which degrade rapidly in most environmental conditions.


Color pigments can be easily suspended in oil, making it suitable as supporting medium for paints. The slow drying process and miscibility of oil facilitates a realistic style. This method has been used since the 15th century.


Crude oil can be processed into plastics and other substances.

Other Usages

Sulfuric acid has been called oil of vitriol in pre-scientific times, due to its syrupy consistency. Even in modern times, sulfuric acid is sometimes called vitriolic acid, and caustic personalities are called "vitriolic." Sulfuric acid is not a petrochemical, and in modern parlance, is not an oil.


Oils have been used throughout history as a fragrant or religious medium. Oil is often seen as a spiritually purifying agent. It is used in religious ceremonies, such as chrism or baptism.


See also

  • Emulsifier, allow oils and water to mix
  • Oil pollution
  • Wax, compounds with oil-like properties that are solid at common temperature
oil in Arabic: زيت
oil in Aragonese: Azeite
oil in Catalan: Oli
oil in Czech: Olej
oil in Welsh: Olew
oil in Danish: Olie
oil in German: Öle
oil in Modern Greek (1453-): Λάδι
oil in Spanish: Aceite
oil in Esperanto: Oleo
oil in Basque: Olio
oil in Persian: روغن
oil in French: Huile
oil in Scottish Gaelic: Ola
oil in Galician: Aceite
oil in Croatian: Ulja
oil in Ido: Oleo
oil in Indonesian: Minyak
oil in Icelandic: Olía
oil in Italian: Olio
oil in Hebrew: שמן
oil in Kongo: Mafuta
oil in Ladino: Azete
oil in Lithuanian: Aliejus
oil in Lingala: Mafúta
oil in Malay (macrolanguage): Minyak
oil in Dutch: Olie
oil in Japanese: 油
oil in Norwegian: Olje
oil in Norwegian Nynorsk: Olje
oil in Polish: Olej
oil in Portuguese: Óleo
oil in Russian: Масло
oil in Simple English: Oil
oil in Slovenian: Olje
oil in Sundanese: Minyak
oil in Finnish: Öljy
oil in Swedish: Olja
oil in Thai: น้ำมัน
oil in Ukrainian: Олія
oil in Yiddish: אויל
oil in Chinese: 油

Synonyms, Antonyms and Related Words

Barbados tar, Haliver Oil, Macassar oil, absinthe, adipose tissue, adulation, aid, alcohol, animal oils, anoint, anthracene oil, aquarelle, asphalt-base oil, avocado oil, balm, balsam, bay oil, beechnut oil, beef tallow, beeswax, benzine, blandishment, blarney, blubber, bone oil, bottlenose oil, briquette, bunker, bunkum, burnable, butane, butter, butter up, butterfat, cajolement, cajolery, camphor, candlenut oil, canvas, carapa oil, carbon, castor oil, cater, cedarwood oil, cerate, charcoal, clear the way, clove oil, coal, coal oil, cocoa butter, cod-liver oil, coke, collyrium, combustible, compliment, copaiba, copra oil, corn oil, creosote, croton oil, dab, daub, demulcent, detonate, doegling oil, dope, dose, drag, dress, dripping, drippings, drug, dub, ease, easel-picture, edible oil, electricity, embrocate, embrocation, emollient, equalize, ethane, ethanol, eucalyptus oil, even, expedite, explain, explode, eyewash, eyewater, facilitate, fair words, fat, fawning, feed, fill up, finger painting, fireball, firing, fish oil, flammable, flammable material, flatten, flattery, flaxseed oil, forage, fuel, fuel additive, fuel dope, fuel oil, fuel up, fulminate, furnace oil, gas, gas carbon, gas oil, gas up, gasoline, get around, ghee, glycerolate, goose grease, gouache, grade, grease, grease the ways, grease the wheels, gum spirit, harrow, hasten, help along, hempseed oil, heptane, hexane, honey, honeyed phrases, honeyed words, illuminant, illuminating gas, incense, inflammable, inflammable material, isooctane, jet fuel, jolly, kekuna oil, kerosene, kid along, lamp oil, lanolin, lard, lard oil, laurel butter, lay, lay it on, lemon oil, level, light source, liniment, linseed oil, lipid, lipoma, loose, lotion, lubricate, luminant, make clear, make way for, margarine, medicate, methane, methanol, mineral oil, mineral seal oil, mineral sperm oil, mineral spirits, mow, mutton tallow, naphthalene, naphthene-base oil, natural gas, nut oil, octane, oil of almonds, oil painting, ointment, oleo, oleomargarine, oleoresin, olive oil, open the way, open up, overdo it, painting, palaver, palm oil, palm-kernel oil, paraffin, pave the way, peanut oil, peat, pentane, perilla oil, petrol, petrolatum, petroleum, petroleum benzine, pine oil, pine tar, pine-tar oil, plane, planish, plaster, play up to, pomade, poppyseed oil, porpoise oil, praise, prepare the way, pretty lies, propane, propellant, provender, provision, purvey, quicken, rape oil, refuel, remove friction, ricinus oil, road oil, rocket fuel, rosin grease, rosin oil, run interference for, salve, saturating oil, seal oil, sell, sesame oil, shale naphtha, shave, shortening, simplify, slick, slick on, smear, smooth, smooth down, smooth out, smooth the way, soap, soap the ways, soft soap, soft-soap, soften up, soybean oil, speed, spikenard, stoke, stove oil, string along, stroke, suet, sweet nothings, sweet talk, sweet words, sycophancy, tallow, technical oil, tempera, top off, turf, turpentine, unbar, unblock, unclog, unction, unguent, unguentum, unjam, victual, vulnerary, wash, wash drawing, water, wax, whale oil, wheedling, wood oil, wool fat
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