Definition of daltonism in US English:

daltonism

noun

  • another term for protanopia, a form of color-blindness
    • ‘The most common form of colorblindness is daltonism or a problem with red/green.’
    • ‘It is one of the tests of reference to screen daltonism.’
    • ‘The number of colour-blind artists in the history of art is probably larger than usually assumed, bur it is not possible to demonstrate daltonism simply by looking at an artist's pictures.’

Origin

Mid 19th century: from the name of John Dalton, John + -ism.

Pronunciation

daltonism

/ˈdɔlt(ə)nˌɪzəm//ˈdôlt(ə)nˌizəm/