Pupil 1 : The aperture of the eye. The pupil controls the total level of light that is passes onto the retina. The pupil of an average adult may dilate to a diameter of 7 mm
Environmental Health and Safety, Glossary, University of Chicago, Illinois, USA 2010. http://safety.uchicago.edu/tools/glossary.shtml, (Ergo - Amer) {753}