diopter

See also: Diopter

English

Alternative forms

• dioptra
• dioptre
• dioptry (obsolete)

Etymology

From Latin dioptra, from Ancient Greek διόπτρα (dióptra). (Can this⁽⁺⁾ etymology be sourced?)

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. (photography, 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.
7. (obsolete) A surgical speculum.
8. (obsolete) An instrument for drawing the skull by projections.

Translations

unit of measure

• Basque: dioptria
• Catalan: diòptria f
• Czech: dioptrie (cs) f
• Finnish: dioptria, diopteri
• German: Dioptrie (de) f
• Hungarian: dioptria (hu)
• Italian: diottria (it) f
• Macedonian: диоптрија f (dioptrija), диоптер m (diopter)
• Polish: dioptria (pl) f
• Portuguese: dioptria f
• Russian: дио́птрия (ru) f (dióptrija)
• Spanish: dioptría (es) f

lens system

• German: Diopter n

theodolite

• Finnish: teodoliitti (fi)
• German: Diopter n

alidade — see alidade

speculum — see speculum

instrument for drawing skull

Anagrams

• dioptre, peridot, periodt, proetid, proteid, protide, pterido-, pteroid, reptoid