Word.ws English Dictionary

dioptry

dioptry is the alternative form of diopter.

Meaning of diopter

Noun

diopter (plural diopters)

  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. (dated) A 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. (obsolete) Any lens system, such as a telescope.
  5. (obsolete) A theodolite or similar surveyor’s angle measuring device.
  6. (obsolete) An alidade.

See all 8 meanings of diopter

Forms of dioptry

pluraldioptries

Questions about dioptry

What is dioptry the alternative form of?
Dioptry is the alternative form of diopter.

Words near dioptry in the dictionary

  1. dioptrical
  2. dioptrically
  3. dioptrics
  4. dioptries
  5. dioptrometry
  6. dioptry
  7. Dioquino Zobel
  8. diorama
  9. dioramas
  10. dioramic
  11. diorchic

Source and license

Adapted from Wiktionary: dioptry (page history and authors); diopter (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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Cite this entry: “dioptry.” Word.ws, https://word.ws/dioptry. Based on Wiktionary, CC BY-SA 4.0.