/ Dictionary / Index P plagiohedral: Meaning and Definition of Find definitions for: pla•gi•o•he•dral Pronunciation: (plā"jē-u-hē'drul), [key] — adj. (of a crystal) having faces arranged obliquely in a helix. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. plagioclase plagiotropic Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language