# Daltonism

> English word · Noun · IPA /ˈdɔːltənɪzəm/

## Definitions
1. An inability or defective ability to perceive or distinguish certain colors, especially red-green color blindness.
2. Achromatopsia.

## Etymology
From Dalton + -ism. Named after John Dalton (1766–1844), who suffered from the condition and conducted early research on it.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/daltonism