Phospholipids (syn.: phosphatides, from the Greek φωσφορᾰ - “light” + λίπιδος - “fat”) - a set of lipids containing phosphoric acid as part of their molecule. Typically, four classes of phospholipids are distinguished depending on the amount of carboxylic acids: neutral fats - glycerophospholipids - cardiolipin - lecithin (phosphatidylcholine) - sphingomyelin - a brain-specific protein compound. There is a variety of this acid - triglyceride, which is palmitic acid and is no longer a phospholipid.