lens

(noun) a transparent optical device used to converge or diverge transmitted light and to form images. Synonyms: lense, lens system.

(noun) genus of small erect or climbing herbs with pinnate leaves and small inconspicuous white flowers and small flattened pods: lentils. Synonyms: Lens, genus Lens.

(noun) (metaphor) a channel through which something can be seen or understood. Example: "The writer is the lens through which history can be seen."

(noun) biconvex transparent body situated behind the iris in the eye; its role (along with the cornea) is to focuses light on the retina. Synonyms: crystalline lens, lens of the eye.

(noun) electronic equipment that uses a magnetic or electric field in order to focus a beam of electrons. Synonyms: electron lens.