"science of sight and the natural properties of light," 1570s, from optic; also see -ics. Used for Medieval Latin optica (neuter plural), from Greek ta optika "optical matters," neuter plural of optikos "optic."

1560s, "relating to or connected with the science of optics; pertaining to vision," from optic + -al (1). Of abstract art, from 1964. In astronomy, in reference to double stars that appear so only because they lie in the same line of sight from earth, by 1868. Optical illusion is attested by 1757. Related: Optically.

late 14c., optik, "of or pertaining to the eye as the organ of vision," from Old French optique, obtique (c. 1300) and directly from Medieval Latin opticus "of sight or seeing," from Greek optikos "of or having to do with sight," from optos "seen, visible," related to ōps "eye," from PIE root *okw- "to see." Meaning "relating to or pertaining to vision or sight" is from 1590s. Optics "eyes" is from 1640s; "formerly the learned and elegant term; afterwards pedantic, and now usually humorous" [OED].

1811, "develop polarization in," in optics, from French polariser, coined by French physicist Étienne-Louis Malus (1775-1812) as a term in optics, from Modern Latin polaris "polar" (see polar). Transferred sense of "to accentuate a division in a group or system" is recorded from 1949 in Arthur Koestler. Related: Polarized; polarizing.

Proto-Indo-European root meaning "to see."

It might form all or part of: amblyopia; antique; antler; atrocity; autopsy; binocle; binocular; biopsy; catoptric; Cyclops; daisy; enoptomancy; eye; eyelet; ferocity; hyperopia; inoculate; inveigle; monocle; monocular; myopia; necropsy; ocular; oculist; oculus; oeillade; ogle; ophthalmo-; optic; optician; optics; optometry; panoptic; panopticon; Peloponnesus; pinochle; presbyopia; prosopopeia; stereopticon; synopsis; triceratops; ullage; wall-eyed; window.

It might also be the source of: Sanskrit akshi "the eye; the number two," Greek osse "(two) eyes," opsis "a sight;" Old Church Slavonic oko, Lithuanian akis, Latin oculus, Greek okkos, Tocharian ak, ek, Armenian akn "eye."

late 14c., perspectif, "the science of optics," from Old French perspective and directly from Medieval Latin perspectiva ars "science of optics," from fem. of perspectivus "of sight, optical" from Latin perspectus "clearly perceived," past participle of perspicere "inspect, look through, look closely at," from per "through" (from PIE root *per- (1) "forward," hence "through") + specere "look at" (from PIE root *spek- "to observe"). The English word is also attested from early 15c. as an adjective, "pertaining to the science of optics."

The sense of "the art of drawing solid objects on a flat surface so as to give appearance of distance or depth" is attested by 1590s, probably by influence of Italian prospettiva, an artists' term. The meaning "proper or just proportion, appropriate relation in the mind of the parts of a subject to one another" is recorded by c. 1600, hence the figurative meaning "mental outlook over time" (1762).

also depolarisation, "act of depriving of polarity or removing the effects of polarization," 1814; see de- + polarization. Perhaps an agent noun to depolarize "deprive of polarity," which is attested from 1813 (implied in depolarized), originally in optics.

in optics, "point or object from which light radiates," 1714; see radiant (adj.). In astronomy, of meteor showers, "the point in the heavens from which the shooting stars seem to proceed," by 1834, in reference to the great shower of the previous November.

early 15c. (Chauliac), "an opening, hole, orifice," from Latin apertura "an opening," from apertus, past participle of aperire "to open, uncover," from PIE compound *ap-wer-yo- from *ap- "off, away" (see apo-) + root *wer- (4) "to cover." In optics, "the diameter of the exposed part of a telescope, microscope, etc.," from 1660s.

1680s, "person skilled in the science of optics, a sense now rare or obsolete; see optic + -ian. In the meaning "one who makes or sells optical instruments" it is attested from 1737, after French opticien "maker or seller of optical instruments," on the model of physician, etc.