Definition of lenses:
(n) :
(optics) An object, usually made of glass, that focuses or defocuses the light that passes through it.
(n) :
(anatomy) The transparent crystalline structure in the eye.
(n) :
A device which focuses or defocuses electron beams.
(n) :
(by extension, figuratively) A way of looking, literally or figuratively, at something.
(n) :
(programming) A construct used in statically-typed functional programming languages to access nested data structures.
(n) :
(earth science) A body of rock, ice, or water shaped like a convex lens.