lipid

lipid A fat. Lipids are vital parts of cells and, with carbohydrates and proteins, are the main constituents of cells. Lipids are easily stored in the body and serve as fuel. Among the well-known lipids are cholesterol, triglycerides, fatty acids, and steroids (such as cortisone). Lipoproteins, glycolipids, and phospholipids are all compound lipids (lipids in combination with other types of chemicals).