: any of numerous unctuous combustible substances that are liquid or can be liquefied easily on warming, are soluble in ether but not in water, and leave a greasy stain on paper or cloth—see essential oil, fatty oil, volatile oil
: a substance (as a cosmetic preparation) of oily consistency <bath oil>
Any greasy substance liquid at room temperature and insoluble in water. It may be a fixed (nonvolatile) oil, an essential oil, or a mineral oil (seepetroleum). Fixed oils and fats (derived from animals and plants) have the same chemical compositionboth are esters of glycerol and fatty acids. These oils have a variety of industrial and food uses. Linseed, tung, and other drying oils are highly unsaturated (seesaturation); these and large quantities of soybean, sunflower, and safflower oils (also constituents of foods) are used in paints and varnishes. When exposed to air they absorb oxygen and polymerize (seepolymerization), forming a tough coating. Some specialty oils and oil derivatives are also used in leather dressing and textile manufacture.