dioptre
noun /daɪˈɒptə(r)/
/daɪˈɑːptər/
(US English diopter)
(physics- a unit for measuring the power of a lens to refract light (= make it change direction)
屈光度（透镜的折射能力单位） 词源late 16th cent. (originally as diopter): from French, from Latin dioptra, from Greek, from di- ‘through’ + optos ‘visible’. The term was used in the early 17th cent. to denote an ancient form of theodolite; the current sense dates from the late 19th cent.