eyesight (n.)

c. 1200, from Old English ege (Mercian), eage (West Saxon) "eye; region around the eye; apperture, hole," from Proto-Germanic *augon (source also of Old Saxon aga, Old Frisian age, Old Norse auga, Swedish öga, Danish øie, Middle Dutch oghe, Dutch oog, Old High German ouga, German Auge, Gothic augo "eye"). Apparently the Germanic form evolved irregularly from PIE root *okw- "to see."

HAMLET: My father — methinks I see my father.

HORATIO: Where, my lord?

HAMLET: In my mind's eye, Horatio.

Until late 14c. the English plural was in -an, hence modern dialectal plural een, ene. Of potatoes from 1670s. Of peacock feathers from late 14c. As a loop used with a hook in fastening (clothes, etc.) from 1590s. The eye of a needle was in Old English. As "the center of revolution" of anything from 1760. Nautical in the wind's eye "in the direction of the wind" is from 1560s.

To see eye to eye is from Isaiah lii.8. Eye contact attested from 1953. To have (or keep) an eye on "keep under supervision" is attested from early 15c. To have eyes for "be interested in or attracted to" is from 1736; make eyes at in the romance sense is from 1837; gleam in (someone's) eye (n.) "barely formed idea" is from 1959. Eye-biter was an old name for "a sort of witch who bewitches with the eyes."

Middle English sight, from Old English sihð, gesiht, gesihð "thing seen; power or faculty of sight; aspect; vision; apparition," from Proto-Germanic *sekh(w)- (source also of Danish sigte, Swedish sigt, Middle Dutch sicht, Dutch zicht, Old High German siht, German Sicht, Gesicht), stem that also yielded Old English seon (see see (v.)), with noun suffix -th (2), later -t (14c.).

The meaning "perception or apprehension by means of the eyes" is from early 13c. The meaning "device on a firearm to assist in aiming" is from 1580s. A "show" of something, hence, colloquially, "a great many; a lot," (late 14c.). As "something that calls forth glances of shock, amusement, etc., a shocking spectacle," by 1862.

Sight for sore eyes "welcome visitor" is attested from 1738; sight unseen (adv.) "without previous inspection" is from 1892. Sight gag is attested by 1944. To feel or know something at first sight is from c. 1300. From the firearm aiming sense come in (one's) sights; have (one's) sights set on something. To keep out of sight is from late 14c.; to be out of (someone's) sight is from c. 1400.