Daltonism

/ˈdɔːltənɪzəm/

//ˈdɔːltənɪzəm// noun

"daltonism" is a 9-letter English headword indexed on PlainSpell.

The verdict

“Daltonism” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
9
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - An inability or defective ability to perceive or distinguish certain colors, especially red-green color blindness.

Corpus desk

Index EN-daltonism · Daltonism · English

Daltonism · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-LONG 9 letters
  • VOW-3 3 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "D" thin
  • PHOTO-UNK Peer pending

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Key facts for Daltonism
PropertyValue
HeadwordDaltonism
LanguageEnglish
Part of speechNoun
IPA/ˈdɔːltənɪzəm/
Letters9
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “Daltonism” in English

Daltonismfalls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

Daltonism is uncommon English outside the top frequency list, classed as anoun, transcribed /ˈdɔːltənɪzəm/. Rarity is why readers land here mid-draft. 2 senses are on record.

No generated misspelling entries exist for Daltonism in our index, typically a sign the spelling maps closely to how the word sounds. No confusable counterpart is on file for this word, since no other headword is close enough in sound or shape to pair with it.

Etymologically, the entry records: From Dalton + -ism. Named after John Dalton (1766–1844), who suffered from the condition and conducted early research on it. The correct English form is Daltonism, spelled D-A-L-T-O-N-I-S-M.

Definition

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

Recorded use

Wiktionary examples

These source excerpts show how Daltonism appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. A person with Daltonism may be said to lack a discriminatory power that others have: his perceptions of red and green are, as such, not to be relied on.
  2. The Ishihara plates were developed for the assessment of congenital colour anomalies (Daltonism) and so there is considerable detail in the testing that is not relevant to optic nerve disease where the losses do not follow the specific patterns seen in Daltonism but show largely global losses.

Etymology

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

Synonyms

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "Daltonism"?
"Daltonism" is spelled D-A-L-T-O-N-I-S-M. The IPA pronunciation is /ˈdɔːltənɪzəm/.
What does "Daltonism" mean?
As a noun, "Daltonism" means: An inability or defective ability to perceive or distinguish certain colors, especially red-green color blindness.
How do you pronounce "Daltonism"?
The IPA (International Phonetic Alphabet) transcription for "Daltonism" is /ˈdɔːltənɪzəm/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "Daltonism"?
From Dalton + -ism. Named after John Dalton (1766–1844), who suffered from the condition and conducted early research on it. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list