DIOPTRES
- DIOPTRE, a measure of refractive power, also DIOPTER [n]
- unit of measure of the refractive power of a lens, having the dimension of the reciprocal of length and a unit equal to the reciprocal of one meter
- DIOPTRE, diopter (a measure of refractive power) [n]
- instrument, invented by Hipparchus, to measure the apparent diameter of the sun or moon or to estimate the size or elevation of distant objects