astigmatism

/əˈstɪɡmətɪzm̩/

//əˈstɪɡmətɪzm̩// noun

"astigmatism" is a 11-letter English headword indexed on PlainSpell.

The verdict

“astigmatism” is uncommon English (frequency #55,927 among 3,931 “A” headwords), classed as a noun. The kind of spelling people second-guess.

#55,927
frequency rank, English
3,931
“A” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A defect of a lens such that light rays coming from a point do not meet at a focal point so that the image is blurred.

Corpus desk

Index EN-astigmatism · astigmatism · English

astigmatism · rank #55,927 · 0 variants · 0 confusables

  • FREQ-RARE #55,927
  • LEN-MEGA 11 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 3,931
  • PHOTO-FINISH Asterix

Nearest frequency peer: Asterix (-1 rank slots)

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.

Long-tail ranks near “astigmatism”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “astigmatism” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for astigmatism
PropertyValue
Headwordastigmatism
LanguageEnglish
Part of speechNoun
IPA/əˈstɪɡmətɪzm̩/
Letters11
Frequency rank#55,927
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “astigmatism” in English

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right).astigmatismfalls in this rarity band:

#1#100#1K#10K#100K
← used constantlyrarely used →

Ticks step logarithmically, so each one marks a roughly tenfold drop in how often the word turns up. Rare peers in the same band: “Asterix” (#55,926), “audiophile” (#55,928), “Asis” (#55,925). Among 3,931 “A” headwords, “astigmatism” is #55,927. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

astigmatism is uncommon English at frequency #55,927 among 3,931 “A” headwords, classed as anoun, transcribed /əˈstɪɡmətɪzm̩/. Rarity is why readers land here mid-draft. 2 senses are on record.

The misspelling generator found no plausible variants for astigmatism, a straightforward case of a spelling with little room for common typos. Our dataset records no confusable match here, a sign it's visually distinctive enough not to be mixed up with another word.

Etymologically, the entry records: From a- (negative prefix) + stem of Ancient Greek στίγμα (stígma, “mark, point”) + -ism. Coined by English polymath William Whewell in 1846. The correct English form is astigmatism, spelled A-S-T-I-G-M-A-T-I-S-M.

Definition

  1. 1
    A defect of a lens such that light rays coming from a point do not meet at a focal point so that the image is blurred.
  2. 2
    A disorder of the vision, usually due to a misshapen cornea, such that light does not focus correctly on the retina causing a blurred image.

Etymology

From a- (negative prefix) + stem of Ancient Greek στίγμα (stígma, “mark, point”) + -ism. Coined by English polymath William Whewell in 1846.

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); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "astigmatism"?
"astigmatism" is spelled A-S-T-I-G-M-A-T-I-S-M. The IPA pronunciation is /əˈstɪɡmətɪzm̩/.
What does "astigmatism" mean?
As a noun, "astigmatism" means: A defect of a lens such that light rays coming from a point do not meet at a focal point so that the image is blurred.
How do you pronounce "astigmatism"?
The IPA (International Phonetic Alphabet) transcription for "astigmatism" is /əˈstɪɡmətɪzm̩/. 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 "astigmatism"?
From a- (negative prefix) + stem of Ancient Greek στίγμα (stígma, “mark, point”) + -ism. Coined by English polymath William Whewell in 1846. 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.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "astigmatism", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 11 letters (nearest by frequency rank).

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

Source: FrequencyWords open word-frequency list