/ Dictionary / Index R rotation axis: Meaning and Definition of Find definitions for: rota'tion ax"is Pronunciation: [key] — Crystall. Crystall. an imaginary line through a crystal about which the crystal may be rotated a specified number of degrees and be brought back to its original position. Also calledCf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rotational quantum number rotation-inversion axis Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language