LDL (low-density lipoprotein): A molecule that is a combination of lipid (fat) and protein. Lipoproteins are the form in which lipids are transported in the blood.
Low-density lipoprotein (LDL) transports cholesterol from the liver to the tissues of the body. LDL cholesterol is therefore considered the "bad" cholesterol.
How to Lower Your Cholesterol & Save Your Heart