I. ˈäp-tik adjective
Etymology: Middle English, from Medieval Latin opticus, from Greek optikos, from opsesthai to be going to see; akin to Greek opsis appearance, ōps eye — more at eye
Date: 14th century
: of or relating to vision or the eye
II. noun
Date: 1600
1. : eye
2.
a. : any of the elements (as lenses, mirrors, or light guides) of an optical instrument or system — usually used in plural
b. : an optical instrument