LDL: Low Density Lipoproteins
Lipoproteins are composed of lipids (fat) and proteins that carry triglycerides, cholesterol, and vitamins (A, D, E, and K) through body fluids (plasma, interstitial fluid, and lymph) to and from tissues. It also absorbs dietary cholesterol and carries them from liver to tissues and vice versa to provide energy.
As lipid is less dense than water (remember how grease floats in a water filled skillet!), lipoproteins are named based on amount of lipid they carry. Hence, low density lipoprotein ( also known as bad cholesterol) carries higher amount of lipid (cholesterol) and high density lipoprotein (HDL, known as good cholesterol) carries least amount of lipid.