__ flare (4)
I believe the answer is:
lens
(Other definitions for lens that I've seen before include "Focusing glass" , "Optical element" , "Through which to view" , "One focusing light" , "Piece of glass in optical instrument" .)
I believe the answer is:
lens
(Other definitions for lens that I've seen before include "Focusing glass" , "Optical element" , "Through which to view" , "One focusing light" , "Piece of glass in optical instrument" .)