/ Dictionary / Index D Daltonian: Meaning and Definition of Find definitions for: Dal•to•ni•an Pronunciation: (dôl-tō'nē-un), [key] — adj. of John Dalton or his atomic theory. of or pertaining to daltonism. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. dalton daltonism Related Content Daily Word Quiz: portent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language