EY, Ey, or ey may refer to:
Eyes are organs of the visual system. They provide organisms vision, the ability to process visual detail, as well as enabling several photo response functions that are independent of vision.
An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as telescopes and microscopes.
"An eye for an eye", or the law of retaliation, is the principle that a person who has injured another person is to be penalized to a similar degree, or in softer interpretations, the victim receives the [estimated] value of the injury in compensation.
The eye is a region of mostly calm weather at the center of strong tropical cyclones. The eye of a storm is a roughly circular area, typically 30–65 km (20–40 miles) in diameter.
Eye tracking is the process of measuring either the point of gaze (where one is looking) or the motion of an eye relative to the head.
Eye movement includes the voluntary or involuntary movement of the eyes, helping in acquiring, fixating and tracking visual stimuli.