Share this entry

Share this page

dioptre

Line breaks: di|optre
Pronunciation: /dʌɪˈɒptə
 
/
(US diopter)

Definition of dioptre in English:

noun

A unit of refractive power, which is equal to the reciprocal of the focal length (in metres) of a given lens: vision corrected to within one dioptre of perfect sight
More example sentences
  • The focusing power of a lens is measured in dioptres.
  • Refractive error is measured in dioptres, and myopia is designated with a minus sign.
  • The difference between the focusing powers of these two axes, measured in dioptres, is the astigmatism.

Origin

late 16th century (originally as diopter, denoting an alidade): from French, from Latin dioptra, from Greek, from di- 'through' + optos 'visible'. The term was used in the early 17th century to denote an ancient form of theodolite; the current sense dates from the late 19th century.

Definition of dioptre in:

Share this entry

Share this page

 

What do you find interesting about this word or phrase?

Get more from Oxford Dictionaries

Subscribe to remove ads and access premium resources

Word of the day prepotent
Pronunciation: ˌprēˈpōtnt
adjective
greater than others in power or influence