/ Dictionary / Index H hemihedral: Meaning and Definition of Find definitions for: hem•i•he•dral Pronunciation: (hem"i-hē'drul), [key] — adj. (of a crystal) having only half the planes or faces required by the maximum symmetry of the system to which it belongs. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hemi-head hemihydrate Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language