The definition of a lens is a piece of glass or other hard clear material molded with one side flat and the other curved or both sides curved that forms an image by bringing together or spreading the light that passes through it.(noun)
See lens in Webster's New World College Dictionary
Origin: L, lentil: from the resemblance to the shape of a lentil
See lens in American Heritage Dictionary 4
noun pl. lens·es
Origin: New Latin lēns
Origin: , from Latin, lentil (from the shape of a double convex lens).
Light rays converge, passing through a biconvex lens (top) and diverge, passing through a biconcave lens (bottom). The label f indicates the focal point.
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