/ Dictionary / Index R rigid motion: Meaning and Definition of Find definitions for: rig'id mo'tion Pronunciation: [key] — Math. Math. any transformation, as a translation or rotation, of a set such that the distance between points is preserved. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rigidize Rigil Kentaurus Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language