adj.
Pronunciation: ' äp-ti-k ə l
Function: adjective
Date: 1570
1 : of or relating to the science of optics
2 a : of or relating to vision : VISUAL b : VISIBLE 1 < optical wavelength> c : of, relating to, or being objects that emit light in the visible range of frequencies <an optical galaxy> d : using the properties of light to aid vision <an optical instrument>
3 a : of, relating to, or utilizing light especially instead of other forms of energy < optical microscopy> b : involving the use of light-sensitive devices to acquire information for a computer < optical character recognition>
4 : of or relating to optical art
– op · ti · cal · ly \ -k( ə -)l ē \ adverb