Eye relief is a term commonly used to describe the distance one needs to hold their eye from an eyepiece or viewfinder in order to see the entire field of view with ease. Synonyms for eye relief include viewing distance, exit pupil distance, and eye-to-lens distance. Other terms that can be used to describe eye relief include eye position, eye point, or eye box. Eye relief is an important factor to consider when choosing binoculars, scopes, or other optical devices, as it can impact the user's comfort and clarity of view.