What do hdl and ldl stand for?

Cholesterol types: High density lipoprotein ( hdl) is also refered to as " good cholesterol" represents the cholesterol being carried away from the cells ( in the garbege trucks) , therefore the higher the better. Low density lipoprotein (ldl) or "bad cholsterol" is in the delivery trucks, therefore the less the better.

Lipoproteins: High density lipoprotein (HDL) and low density lipoprotein (ldl) are particles that carry cholesterol in the blood. The number of LDL and HDL particles in blood are the best measures of LDL and HDL quantity. Cholesterol carried in these particles (ldl-c and hdl-c) provide a general, but often inaccurate, estimate of LDL and HDL levels.