Noun: dioptre dI'óp-tu(r)
Usage: Brit, Cdn (US: diopter)
Usage: Brit, Cdn (US: diopter)
- 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
"Her new glasses had a prescription of +2.5 dioptres";
- diopter
Derived forms: dioptres
Type of: unit, unit of measurement
Encyclopedia: Dioptre