[ dawl-tn-iz-uh m ]
/ ˈdɔl tnˌɪz əm /

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 forms

dal·ton·ic [dawl-ton-ik] /dɔlˈtɒn ɪk/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for daltonic


/ (ˈdɔːltəˌnɪzəm) /


colour blindness, esp the confusion of red and green

Derived Forms

daltonic (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

Medicine definitions for daltonic


[ dôltə-nĭz′əm ]


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.