optic

Etymology

Borrowed from Middle French optique or Medieval Latin opticus, from Ancient Greek ὀπτῐκός (optikós, “of or for sight”), from ὀπτός (optós, “visible”) + -ῐκός (-ikós, “-ic”, adjectival suffix).

adj

1. (relational) Of, or relating to the eye or to vision.
2. (optics, relational) Of, or relating to optics or optical instruments.

noun

1. (archaic, humorous) An eye.
   The difference is as great between / The optics seeing, as the object seen. 1734, Alexander Pope, Of the Knowledge and Characters of Men: An Epistle to the Right Honourable Richard Lord Viscount Cobham
   how they, / Who saw those figures on the margin kiss all, / Could turn their optics to the text and pray, / Is more than I know[…] 1819, Lord Byron, “Canto 1”, in Don Juan, section 46
2. (optics) A lens or other part of an optical instrument that interacts with light.
   The single-imaging optic of the mammalian eye offers some distinct visual advantages. Such lenses can take in photons from a wide range of angles, increasing light sensitivity. They also have high spatial resolution, resolving incoming images in minute detail. 2013, Fenella Saunders, “Tiny Lenses See the Big Picture”, in American Scientist, volume 101, number 4, →DOI, page 270
3. (trademark in UK) A measuring device with a small window, attached to an upside-down bottle, used to dispense alcoholic drinks in a bar.
   They were neatly lined up on three shelves between the optics of martini, vodka, whisky and gin. 2014, M. P. Wright, Heartman
   They pulled up two bar stools and looked around the room as the barman relieved the whisky optic of its contents. 2018, Denise Mina, Exile