An object, usually made of glass, that focuses or defocuses the light that passes through it.
A device which focuses or defocuses electron beams.
A convex shape bounded by two circular arcs, joined at their endpoints, the corresponding concave shape being a lune.
A genus of the legume family; its bean.
The transparent crystalline structure in the eye.
(earth science) A body of rock, ice, or water shaped like a convex lens.
A construct used in statically-typed functional programming languages to access nested data structures.
(by extension) A way of looking, literally or figuratively, at something.
