Definition of diopter in English:

Share this entry

diopter

Pronunciation: /dīˈäptər/

noun

A unit of refractive power that is equal to the reciprocal of the focal length (in meters) of a given lens.
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 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.

For editors and proofreaders

Syllabification: di·op·ter

Share this entry
 

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.