The term oil (Hebrew: שֶׁמֶן, shemen meaning "grease", Hebrew: יִצְהָ֔ר, yishār meaning "olive oil", "shining"; Greek: ἔλαιον, elaion, "oil", "olive oil") refers to a class of substances which, by convention, should be presented as a viscous liquid at ambient conditions of temperature and pressure at sea level. Oils are generally unctuous, slippery and combustible at room temperatures and soluble in various organic solvents such as alcohols or ethers but not in water. Oil is also a neutral and nonpolar chemical substance. Oils may be animal, vegetable, or petrochemical in origin, and may be volatile or non-volatile; Oils are used in a great variety of products, especially lubricants and fuels.
Olive oil, used as ointment, was an important feature of ancient medical treatment as we see in Isaiah 1:6 . An oil treasury was among the assets stored by Jewish kings (2Kings 20:13 ). Oil was an indicative of joy and gladness (Isaiah 61:3 ).
Use in Christianity
Oils can be used as food or for food preparation. Deep frying is a common method of food preparation and is used both in home and in industry. After prolonged use, the fat or frying oil has substantially altered its chemical and physical properties. Cooking oils are derived either from animal fat or plant oils. Examples of animal fat are butter, hog (called lard) and marine oils like whale and herring oils among others. Plant oils can be extracted from the fruits of the olive tree and several oil palm species. They can also be obtained from seed. Some seed oil has been of great importance in large scale industrial production of edible oils. Common plant oils are olive, corn, palm and sunflower oils among others. Canola oil is obtained from a genetic improvement of rapeseed with much less erucic acid.
Oils are commonly used as lubricants. Mineral oils are most commonly used as lubricants for machines than biological oils. Viscosity is an important characteristic of motor oils. The viscosity of a simple oil is its resistance to flow. It increases as the temperature decreases. For instance, an SAE 40 oil is appropriate for an auto engine in the summer season. However it would be too viscous in the winter. An oil designated as SAE 10W/40 is an oil mixture that behaves like an SAE 40 oil in the summer and like a SAE 10 oil in the winter.
Since ancient times the oil has been used in cosmetics. Oil was used by Jews for anointing the body after the bath for a smooth and gracious appearance.
Greeks and Romans used to anoint the bodies of their dead probably as an antiseptic.
Oil was used in lamps with cotton wicks (Mathew 25:1-9 ). In Judaism, olive oil was used as a fuel to the Menorah of the Temple, as a fuel to the Sabbath lamp and as a preferred choice of fuel oil for the lights kindled at the party of Chanukah.
- Algae to Crude Oil: Million-Year Natural Process Takes Minutes in the Lab With the use of heat and pressure biotechnologists are converting a wet algae slurry into oil, a process likely similar to how oil formed rapidly during the global deluge. Science Daily, December 18, 2013.
- Unger, Merrill F (1988). Harrison, R. K.. ed. The New Unger´s Bible Dictionary. Chicago: Moody Press. pp. 936-939. ISBN 0-8024-9037-9.
- Belitz, H. D; Grosch, W,; Schieberle, P John M (2009). Food Chemistry (4th ed.). Berlin Heidelberg: Springer. p. 647. ISBN 978-3-540-69933-0.
- Ebbing, Darrell D.; Gammon, Steven D (2009). General Chemistry (9th ed.). Boston: Houghton Mifflin Company. p. 436. ISBN 978-0-618-85748-7.
- Unterman, Alan (1997). Dictionary of Jewish Lore & Legend. Thames and Hudson. ISBN 978-0500279847.