تلفظ بین المللی : /ˌɒpsɪˈɒmɪtə/ تلفظ : [,0psI2;'0mIt3]
English
An instrument for measuring the limits of distincts
vision in different individuals, and thus determiming the proper focal
length of a lens for correcting imperfect sight.
(a) The length of a perpendicular drawn from one extremity of an arc of a circle to the diameter drawn through the other extremity. (b) The perpendicular itself. See Sine of angle, below. Artificial sines, logarithms...
