A transparent, encapsulated, nearly spherical structure located behind the pupil of vertebrate eyes, and in the complex eyes of many invertebrates, that focuses light rays on the retina. Also known as crystalline lens.

A dielectric or metallic structure that is transparent to radio waves and can bend them to produce a desired radiation pattern; used with antennas for radar and microwave relay systems.

See <<magnetic lens>>

See <<electron lens>>

1. A geologic deposit that is thick in the middle and converges toward the edges, resembling a convex lens.

2. An irregularly shaped formation consisting of a porous, permeable sedimentary deposit surrounded by impermeable rock.

See <<acoustic lens>>

A curved piece of ground and polished or molded material, usually glass, used for the refraction of light, its two surfaces having the same axis; or two or more such surfaces cemented together. Also known as optical lens.