dioptre

British

/ daɪˈɒptə /

noun

a unit for measuring the refractive power of a lens: the reciprocal of the focal length of the lens expressed in metres

"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

Other Word Forms

dioptral

adjective

Etymology

Origin of dioptre

C16: from Latin dioptra optical instrument, from Greek, from dia- through + opsesthai to see

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Enough, we must not over-rate the value of the objective determination of the error of refraction, and I would estimate the limit of error at half a dioptre at least.

From Schweigger on Squint A Monograph by Dr. C. Schweigger by Schweigger, C.

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023