Definition:
dioptres
- dioptresinstrument, invented by Hipparchus, to measure the apparent diameter of the sun or moon or to estimate the size or elevation of distant objects
- dioptresunit 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
- dioptresDIOPTRE, a measure of refractive power, also DIOPTER