dioptre
tər noun
1.
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
2.
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.
Also, especially British, di·op·tre.
Origin:
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
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
Related forms
di·op·tral, adjective
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2013.
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Based on the Random House Dictionary, © Random House, Inc. 2013.
Cite This Source
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Link To dioptre
Collins
World English Dictionary
dioptre or diopter (daɪˈɒptə) ![[Click for IPA pronunciation guide]](http://static.sfdict.com/dictstatic/g/d/dictionary_questionbutton_default.gif) | |
| —n | |
| a unit for measuring the refractive power of a lens: the reciprocal of the focal length of the lens expressed in metres | |
| [C16: from Latin dioptra optical instrument, from Greek, from dia- through + opsesthai to see] | |
| diopter or diopter | |
| —n | |
| [C16: from Latin dioptra optical instrument, from Greek, from dia- through + opsesthai to see] | |
| di'optral or diopter | |
| —adj | |
00:10
Dioptre
is always a great word to know.
So is interrobang. Does it mean:
| a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question. |
| an extraordinary or unusual thing, person, or event; an exceptional example or instance. |
| dioptre or diopter (daɪˈɒptə) | |
| —n | |
| a unit for measuring the refractive power of a lens: the reciprocal of the focal length of the lens expressed in metres | |
| [C16: from Latin dioptra optical instrument, from Greek, from dia- through + opsesthai to see] | |
| diopter or diopter | |
| —n | |
| [C16: from Latin dioptra optical instrument, from Greek, from dia- through + opsesthai to see] | |
| di'optral or diopter | |
| —adj | |
Collins English Dictionary - Complete & Unabridged 10th Edition
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Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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American Heritage
Medical Dictionary
diopter di·op·ter (dī-ŏp'tər)
n.
Abbr. D.
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.
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Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
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