Standard Lemma guide
Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.
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noun
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.
Definition source: English Wiktionary via Wiktextract
No example sentence was provided for this meaning.
Synonyms: none provided
Antonyms: none provided
noun
The dioptre adjustment mechanism of a pair of binoculars or of a camera viewfinder.
Definition source: English Wiktionary via Wiktextract
No example sentence was provided for this meaning.
Synonyms: none provided
Antonyms: none provided
noun
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".
Definition source: English Wiktionary via Wiktextract
Usage: dated
Topics: arts, hobbies, lifestyle, photography
No example sentence was provided for this meaning.
Synonyms: none provided
Antonyms: none provided
noun
Any lens system, such as a telescope.
Definition source: English Wiktionary via Wiktextract
Usage: obsolete
No example sentence was provided for this meaning.
Synonyms: none provided
Antonyms: none provided
noun
A theodolite or similar surveyor’s angle measuring device.
Definition source: English Wiktionary via Wiktextract
Usage: obsolete
No example sentence was provided for this meaning.
Synonyms: none provided
Antonyms: none provided
noun
An alidade.
Definition source: English Wiktionary via Wiktextract
Usage: obsolete
No example sentence was provided for this meaning.
Synonyms: none provided
Antonyms: none provided
noun
A surgical speculum.
Definition source: English Wiktionary via Wiktextract
Usage: obsolete
No example sentence was provided for this meaning.
Synonyms: none provided
Antonyms: none provided
noun
An instrument for drawing the skull by projections.
Definition source: English Wiktionary via Wiktextract
Usage: obsolete
No example sentence was provided for this meaning.
Synonyms: none provided
Antonyms: none provided
noun
a unit of measurement of the refractive power of a lens which is equal to the reciprocal of the focal length measured in meters; used by oculists
Definition source: Princeton WordNet 3.0
No example sentence was provided for this meaning.
Synonyms: dioptre
Antonyms: none provided
Broader terms: unit of measurement, unit
History
From Latin dioptra, from Ancient Greek διόπτρα (dióptra).
Across languages
18 source translations are retained for this English entry.
