/ Dictionary / Index H high-density lipoprotein: Meaning and Definition of Find definitions for: high'-den'sity lipopro'tein Pronunciation: [key] a blood constituent involved in the transport of cholesterol and associated with a decreased risk of atherosclerosis and heart attack. Abbr.: HDL Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. high-density high-density polyethylene Related Content Daily Word Quiz: pugilist Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language