Definiciones
1.NounA unit of measure of the power of a lens or mirror, equal to the reciprocal of its focal length in meters. Myopia is diagnosed and measured in diopters.
2.NounThe dioptre adjustment mechanism of a pair of binoculars or of a camera viewfinder.
3.NounA lens element attached to the front of a photographic lens to shorten the lens's minimum focus distance; also called a "close-up filter".
4.NounAny lens system, such as a telescope.
5.NounA theodolite or similar surveyor’s angle measuring device.
6.NounAn alidade.
7.NounA surgical speculum.
8.NounAn instrument for drawing the skull by projections.