[ 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
British Dictionary definitions for dioptre
/ (daɪˈɒptə) /
a unit for measuring the refractive power of a lens: the reciprocal of the focal length of the lens expressed in metres
Derived forms of dioptredioptral, adjective
Word Origin for dioptre
C16: from Latin dioptra optical instrument, from Greek, from dia- through + opsesthai to see
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Medical definitions for dioptre
[ 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.