from
WordNet (r) 3.0 (2006)
lens
n 1: a transparent optical device used to converge or diverge
transmitted light and to form images [syn: {lens}, {lense},
{lens system}]
2: genus of small erect or climbing herbs with pinnate leaves
and small inconspicuous white flowers and small flattened
pods: lentils [syn: {Lens}, {genus Lens}]
3: (metaphor) a channel through which something can be seen or
understood; "the writer is the lens through which history can
be seen"
4: biconvex transparent body situated behind the iris in the
eye; its role (along with the cornea) is to focuses light on
the retina [syn: {lens}, {crystalline lens}, {lens of the
eye}]
5: electronic equipment that uses a magnetic or electric field
in order to focus a beam of electrons [syn: {lens}, {electron
lens}]
from
The Collaborative International Dictionary of English v.0.48
Lens \Lens\ (l[e^]nz), n.; pl. {Lenses} (-[e^]z). [L. lens a
lentil. So named from the resemblance in shape of a double
convex lens to the seed of a lentil. Cf. {Lentil}.] (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.
[1913 Webster] Lenses
[1913 Webster]
Note: Of spherical lenses, there are six varieties, as shown
in section in the figures herewith given: viz., a
plano-concave; b double-concave; c plano-convex; d
double-convex; e converging concavo-convex, or
converging meniscus; f diverging concavo-convex, or
diverging meniscus.
[1913 Webster]
{Crossed lens} (Opt.), a double-convex lens with one radius
equal to six times the other.
{Crystalline lens}. (Anat.) See {Eye}.
{Fresnel lens} (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.
{Multiplying lens} or {Multiplying glass} (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.
{Polyzonal lens}. See {Polyzonal}.
[1913 Webster]