diopter
noun
diopter is spelled D-I-O-P-T-E-R: 7 letters. It appears about once in every 16 million words in written English, the 121,279th most frequent word form (wordfreq, 2021 data). As a noun, diopter means “A unit of measure of the power of a lens or mirror, equal to the reciprocal of its focal length in meters. Myopia is diagnosed and measured in…” (English Wiktionary, September 2026). The plural of diopter is diopters.
How many letters and syllables are in diopter?
| Letters | 7: D-I-O-P-T-E-R |
|---|---|
| In writing | about once in every 16 million words; the 121,279th most frequent word form |
| Wrong spellings searched | none measured in search |
| Same letters |
Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media); rhymes and same-letter words are computed by PlainSpell from its own word list.
How common is diopter?
Diopter appears about once in every 16 million words in written English, the 121,279th most frequent word form in the list.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How do you pronounce diopter?
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: LL-Q1860_(eng)-Vealhurl-diopter.wav, Wikimedia Commons (author and licence on each file's page).
What rhymes with diopter?
No other word on PlainSpell ends in the same sounds as diopter.
Spelled with the same letters in another order: peridot.
Computed by PlainSpell from the pronunciations in the English Wiktionary (dump of September 2, 2026): a rhyme shares every sound from the last stressed vowel to the end; ordered by written frequency (wordfreq 3.1).
Forms of diopter
- diopters plural
- dioptra
- dioptre
- dioptry
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
What does diopter mean?
The meanings the English Wiktionary records, quoted as written there (source below).
noun
- 1
A unit of measure of the power of a lens or mirror, equal to the reciprocal of its focal length in meters. Myopia is diagnosed and measured in diopters.
- 2
The dioptre adjustment mechanism of a pair of binoculars or of a camera viewfinder.
- 3
datedA lens element attached to the front of a photographic lens to shorten the lens's minimum focus distance; also called a "close-up filter".
- 4
obsoleteAny lens system, such as a telescope.
- 5
obsoleteA theodolite or similar surveyor’s angle measuring device.
- 6
obsoleteAn alidade.
- 7
obsoleteA surgical speculum.
- 8
obsoleteAn instrument for drawing the skull by projections.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
Diopter in Spanish, French, German and Portuguese
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.
Where does diopter come from?
From Latin dioptra, from Ancient Greek διόπτρα (dióptra).
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).