/ Dictionary / Index S space group: Meaning and Definition of Find definitions for: space' group" Pronunciation: [key] — Crystall. Crystall. a set of symmetry elements that brings a periodic arrangement of points on a Bravais space lattice to its original position. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. spaceflight space heating Related Content Daily Word Quiz: winsome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language