The term lipid commonly refers to fats, which are known chemically as triglycerides. Triglycerides are organic molecules that contain three different types of elements: carbon, hydrogen, and oxygen. But technically, lipids are a class of molecules that includes triglycerides, phospholipids, steroids, and waxes. So if you wanted to know what elements are found in lipids as a class, you'd have to allow for phosphorus as well, since phospholipids contain phosphorus in addition to carbon, hydrogen, and oxygen.