Diopter
Diopter , noun
[Latin dioptra, from Greek {not transcribed}. See 2d Dioptric.]
An optical instrument, invented by Hipparchus, for taking altitudes, leveling, etc.
Also: Dioptra
Diopter , noun
[Latin dioptra, from Greek {not transcribed}. See 2d Dioptric.]
Also: Dioptra