/ Dictionary / Index H HDL: Meaning and Definition of Find definitions for: HDL Pronunciation: [key] See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: hdl (Thesaurus) hdkf. H. Doc. Related Content Daily Word Quiz: ablution Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language