diopter

American  

[dahy-op-ter] / daɪˈɒp tər /

especially British, dioptre

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. 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.

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Other Word Forms

• dioptral adjective

Etymology

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

Example Sentences

The handmade quality of the film is reflected in the many manual filmmaking techniques on display, such as split diopter shots, optical wipes and irises.

From Los Angeles Times • Aug. 23, 2024

In Optica, Optica Publishing Group's journal for high-impact research, the researchers describe the new lens, which they call the spiral diopter.

From Science Daily • Feb. 8, 2024

Even after adjusting the diopter, white text on the outer edges of the EVF has green and red shifts that I never got used to.

From The Verge • Sep. 8, 2022

The ratings of +1, +1.25, +1.5 are in units of diopter strength.

From Washington Post • Jul. 17, 2022

The diffusion waves in this case emanate from the principal focus of the diopter, and therefore become plane on passing through the convex surface of the denser gelatine.

From The Mechanism of Life by Leduc, Stéphane