[dawl-tn-iz-uh m]

noun (sometimes initial capital letter) Pathology.

color blindness, especially the inability to distinguish red from green.

Origin of daltonism

1835–45; J. Dalton + -ism
Related formsdal·ton·ic [dawl-ton-ik] /dɔlˈtɒn ɪk/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for daltonism


Examples from the Web for daltonism

Historical Examples of daltonism

  • Certain authorities on art are said to regard the great Montalbanais as a victim of daltonism—in other words, colour-blind!

    In the Heart of Vosges

    Matilda Betham-Edwards

  • Daltonism, dal′ton-izm, n. colour-blindness: inability to distinguish certain colours.

  • An interesting example is the common type of color blindness known as Daltonism.


    Ernest G. Martin

  • Colour-blindness or Daltonism has been recorded (Horner) through the males only of seven generations.

  • The diseases known as Daltonism or colour-blindness, and hmophilia or the bleeding disease, are certainly hereditary.

    Parenthood and Race Culture

    Caleb Williams Saleeby

British Dictionary definitions for daltonism



colour blindness, esp the confusion of red and green
Derived Formsdaltonic (dɔːlˈtɒnɪk), adjective

Word Origin for daltonism

C19: from French daltonisme, after John Dalton
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

daltonism in Medicine




An inherited defect in the perception of red and green; red-green colorblindness.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.