English dictionary

diopter

/d/aI/'/A/pt/@/r/

Definitions, examples, synonyms and antonyms from WordNet 3.0.

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

noun.quantity

Synonyms dioptre

Source: WordNet 3.0
An optical instrument, invented by Hipparchus, for taking altitudes, leveling, etc.

noun

Source: webster1913