diopter

[ dahy-op-ter ]
/ daɪˈɒp tər /

noun

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.
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 diopter

di·op·tral, adjective

Words nearby diopter

diophantine equation, diophantus, diopside, diopsimeter, dioptase, diopter, dioptometer, dioptre, dioptric, dioptric aberration, dioptrics

British Dictionary definitions for dioptre

dioptre

US diopter

/ (daɪˈɒptə) /

noun

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 dioptre

dioptral, adjective

Word Origin for dioptre

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

Medical definitions for dioptre

diopter
[ dī-ŏp′tər ]

n.

A unit of measurement of the refractive power of lenses equal to the reciprocal of the focal length measured in meters.