/ Dictionary / Index A anomalous dispersion: Meaning and Definition of Find definitions for: anom'alous disper'sion Pronunciation: [key] — Physics. Physics. a sudden change in the refractive index of a material for wavelengths in the vicinity of absorption bands in the spectrum of the material. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. anomalous anomalous Zeeman effect Related Content Daily Word Quiz: rarefied Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language