/ Dictionary / Index R reflection plane: Meaning and Definition of Find definitions for: reflec'tion plane" Pronunciation: [key] — Crystall. Crystall. a plane through a crystal that divides the crystal into two halves that are mirror images of each other. Also calledCf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. reflection nebula reflective Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language