/ Dictionary / Index H hydrargillite: Meaning and Definition of Find definitions for: hy•drar•gil•lite Pronunciation: (hī-drär'ju-līt"), [key] — n. Mineral. gibbsite. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hydrarch hydrargyrism Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language