/ Dictionary / Index W white rat: Meaning and Definition of Find definitions for: white' rat' Pronunciation: [key] an albino variety of the Norway rat, Rattus norvegicus, used in biological experiments. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. white rainbow White River Related Content Daily Word Quiz: tactful Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language