diopter

Fetched 2026-10-26 (cache).

Synonyms: dipter

Antonyms: dipter

Related words from Datamuse; suggestions, not definitions.

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|Myopia]] is diagnosed and measured in diopters.
2. The dioptre adjustment mechanism of a pair of binoculars or of a camera viewfinder.
3. {{lb|en|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. {{lb|en|obsolete}} Any lens system, such as a [[telescope]].
5. {{lb|en|obsolete}} A [[theodolite]] or similar surveyor’s angle measuring device.
6. {{lb|en|obsolete}} An [[alidade]].
7. {{lb|en|obsolete}} A [[surgical]] [[speculum]].
8. {{lb|en|obsolete}} An instrument for drawing the skull by projections.

Source: Wiktionary · CC BY-SA 4.0 (Wiktionary dump) · cached copy, not a rewrite.