Lipid

Any of the large group of fats, oils, waxes, sterols, and triglycerides that occur in living organisms and are characteristically soluble in certain organic solvents but only partially soluble in water; they are oily to the touch. With carbohydrates and proteins, lipids are one of three types of materials that compose living cells. The structure of lipids range from simple straight chain hydrocarbon to complex ring structures. They can be subdivided as 1) fatty acids, 2) neutral fats, 3) phospholipids, 4) glycolipids, 5) aliphatic alcohols and waxes, 6) terpenes, and 7) steroids.