Definition of eye-box in US English:

eye-box

noun

  • 1A box that provides a means of viewing or observing in a particular way.

  • 2The volume of space within which an effectively viewable image is formed by a lens system or visual display, representing a combination of exit pupil size and eye relief distance.

Origin

Late 17th century; earliest use found in John Flamsteed (1646–1719), astronomer.