n.
   - a piece of glass or other transparent material with one or both sides curved for concentrating or dispersing light rays. 
▸Anatomy  the transparent elastic structure behind the iris by which light is focused on to the retina of the eye.
 ▸short for contact lens.
 - the light-gathering device of a camera, containing a group of compound lenses.
 - Physics  an object or device which focuses or otherwise modifies a beam of radiation, sound, electrons, etc.
 
 
  Derivative
  
    - lensed adj.
  - lensless adj.
 
   
  Etymology
  C17: from L., ‘lentil’ (because of the similarity in shape).