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.
Rhom"bic (?), a. 1. Shaped like a rhomb.