What is hdl an abbreviation for?

HighDensityLipoprote: Hdl = high density lipoproteins, particles which carry fat molecules in water outside cells, have complex protein shells (including a key organizing protein: alpha-lipoprotein) which interact with proteins on cell membranes &, if recruited by the cell, is ingested & loaded with fat, then spit back out to remove fat molecules from cells which need to unload fat else die; i.e. May be antiatherogenic.