lens

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A ground or molded piece of glass, plastic, or other transparent material with opposite surfaces either or both of which are curved, by means of which light rays are refracted so that they converge or diverge to form an image.
• noun A combination of two or more such pieces, sometimes with other optical devices such as prisms, used to form an image for viewing or photographing.
• noun A thin piece of glass or plastic, as on a pair of sunglasses, that transmits light without refraction.
• noun A device or phenomenon (such as a gravitational field) that causes light or other radiation to converge or diverge by an action analogous to that of a lens.
• noun A transparent, biconvex structure in the eye of a vertebrate or cephalopod that is located between the iris and the vitreous humor and focuses light rays entering through the pupil to form an image on the retina.
• noun A similar structure in many invertebrates.
• transitive verb Informal To make a photograph or movie of.
• transitive verb To bend or distort (light, for example) by means of a lens, especially a gravitational field.

from The Century Dictionary.

• noun A genus of dicotyledonous plants of the family Mimosaceæ. There are about 14 species, of which the best-known is L. phaseoloides, the match-box bean or simitar-pod. See Entada, gogo, sea-bean, 1, and simitar-pod.
• noun In entomology: The crystalline lens or cone.
• noun One of the facets of the compound eye.
• noun In geology, a body of ore having a lenticular shape.
• noun A surface-condenser made of two round, dished plates bolted together, resembling in form a double-convex lens.
• noun A piece of transparent substance bounded by two curved surfaces (usually spherical), or by a curved surface and a plane.
• noun In anatomy, in the eye, a double-convex body placed in the axis of vision behind the iris between the aqueous humor and the vitreous humor, serving to focus rays of light upon the retina; the crystalline lens. See first cut under eye.
• noun Figuratively, photography, from the use of lenses in that art.
• noun A genus of leguminous plants of the tribe Vicieæ.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Opt.) A piece of glass, or other transparent substance, ground with two opposite regular surfaces, either both curved, or one curved and the other plane, and commonly used, either singly or combined, in optical instruments, for changing the direction of rays of light, and thus magnifying objects, or otherwise modifying vision. In practice, the curved surfaces are usually spherical, though rarely cylindrical, or of some other figure.
• noun (Opt.) a double-convex lens with one radius equal to six times the other.
• noun (Anat.) See Eye.
• noun (Opt.) a compound lens formed by placing around a central convex lens rings of glass so curved as to have the same focus; used, especially in lighthouses, for concentrating light in a particular direction; -- so called from the inventor.
• noun (Opt.) a lens one side of which is plane and the other convex, but made up of a number of plane faces inclined to one another, each of which presents a separate image of the object viewed through it, so that the object is, as it were, multiplied.
• noun See Polyzonal.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An object, usually made of glass, that focuses or defocuses the light that passes through it.
• noun A device which focuses or defocuses electron beams.
• noun geometry A convex shape bounded by two circular arcs, joined at their endpoints, the corresponding concave shape being a lune.
• noun biology A genus of the legume family; its bean.
• noun anatomy The transparent crystalline structure in the eye.
• noun by extension, figuratively A way of looking, literally or figuratively, at something.
• verb transitive To film, shoot.
• verb geology To become thinner towards the edges.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun biconvex transparent body situated behind the iris in the eye; its role (along with the cornea) is to focuses light on the retina
• noun (metaphor) a channel through which something can be seen or understood
• noun a transparent optical device used to converge or diverge transmitted light and to form images
• noun genus of small erect or climbing herbs with pinnate leaves and small inconspicuous white flowers and small flattened pods: lentils
• noun electronic equipment that uses a magnetic or electric field in order to focus a beam of electrons