catflap.org Online Dictionary Query

  Rhomb \Rhomb\ (r[o^]mb or r[o^]m; 277), n. [L. rhombus, Gr.
     "ro`mbos rhomb, a spinning top, magic wheel, fr. "re`mbein to
     turn or whirl round, perhaps akin to E. wrench: cf. F.
     rhombe. Cf. Rhombus, Rhumb.]
     1. (Geom.) An equilateral parallelogram, or quadrilateral
        figure whose sides are equal and the opposite sides
        parallel. The angles may be unequal, two being obtuse and
        two acute, as in the cut, or the angles may be equal, in
        which case it is usually called a square.
        [1913 Webster]
  
     2. (Geom.) A rhombohedron.
        [1913 Webster]
  
     Fresnel's rhomb (Opt.), a rhomb or oblique parallelopiped
        of crown or St. Gobain glass so cut that a ray of light
        entering one of its faces at right angles shall emerge at
        right angles at the opposite face, after undergoing within
        the rhomb, at other faces, two reflections. It is used to
        produce a ray circularly polarized from a plane-polarized
        ray, or the reverse. --Nichol.
        [1913 Webster]

  
  
     2. (Geom.) A rhombohedron.
  
     Fresnel's rhomb (Opt.), a rhomb or oblique parallelopiped
        of crown or St. Gobain glass so cut that a ray of light
        entering one of its faces at right angles shall emerge at
        right angles at the opposite face, after undergoing within
        the rhomb, at other faces, two reflections. It is used to
        produce a ray circularly polarized from a plane-polarized
        ray, or the reverse. --Nichol.

  Fresnel's rhomb
     n.
     A rhombus or oblique parallelopiped of glass cut so that a ray of
  light entering one of its faces at right angles shall emerge at right
  angles at the opposite face, after undergoing within the rhombus, at
  other faces, two reflections. It is used to produce a ray circularly
  polarized from a plane-polarized ray, or the reverse.

  Fresnel's rhomb
     n.
     A rhombus or oblique parallelopiped of glass cut so that a ray of
  light entering one of its faces at right angles shall emerge at right
  angles at the opposite face, after undergoing within the rhombus, at
  other faces, two reflections. It is used to produce a ray circularly
  polarized from a plane-polarized ray, or the reverse.

  Fresnel's rhomb
     n.
     A rhombus or oblique parallelopiped of glass cut so that a ray of
  light entering one of its faces at right angles shall emerge at right
  angles at the opposite face, after undergoing within the rhombus, at
  other faces, two reflections. It is used to produce a ray circularly
  polarized from a plane-polarized ray, or the reverse.

  Fresnel's rhomb
     n.
     A rhombus or oblique parallelopiped of glass cut so that a ray of
  light entering one of its faces at right angles shall emerge at right
  angles at the opposite face, after undergoing within the rhombus, at
  other faces, two reflections. It is used to produce a ray circularly
  polarized from a plane-polarized ray, or the reverse.