dioptral
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dioptral — di·op·tral … English syllables
dioptral — (ˈ)dī|äptrəl adjective Etymology: Latin dioptra + English al : relating to a diopter or to focal power in diopters … Useful english dictionary
diopter — dioptral, adj. /duy op teuhr/, n. 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. Abbr.: D 2. an instrument, invented by Hipparchus … Universalium
diopter — or dioptre [dī äp′tər] n. [Fr dioptre < L dioptra < Gr instrument for leveling, etc. < dia , through + base of opsis, sight < ops, EYE] a unit of measure of the power of a lens, equal to the power of a lens with a focal length of one… … English World dictionary
dioptric — [dī äp′trik] adj. [Gr dioptrikos, relating to the DIOPTER] 1. of optical lenses or the method of numbering them according to their refractive powers; dioptral 2. of dioptrics; refractive 3. helping the sight by refractive correction: Also… … English World dictionary
