[ dahy-op-ter ]
/ daɪˈɒp tər /
Optics. a 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. Abbreviation: D
an instrument, invented by Hipparchus, to measure the apparent diameter of the sun or moon or to estimate the size or elevation of distant objects.
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Also especially British, di·op·tre.
Origin of diopter
1585–95; < Latin dioptra < Greek: instrument for measuring height or levels, equivalent to di- di-3 + op- (for ópsesthai to see) + -tra noun suffix of means
OTHER WORDS FROM diopterdi·op·tral, adjective
Words nearby diopter
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020
Example sentences from the Web for diopter
Diopter, the unit in terms of which the power of a lens or curved mirror can be expressed.The New Gresham Encyclopedia|Various
The unit of power employed by spectacle-makers is termed the diopter or dioptric (see Spectacles).
Medical definitions for diopter
[ dī-ŏp′tər ]
A unit of measurement of the refractive power of lenses equal to the reciprocal of the focal length measured in meters.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.