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 ]

a. 1. Shaped like a rhomb. [ 1913 Webster ]

2. (Crystallog.) Same as Orthorhombic. [ 1913 Webster ]

n. [ Rhomb + ganoid. ] (Zool.) A ganoid fish having rhombic enameled scales; one of the Rhomboganoidei. [ 1913 Webster ]

‖n. pl. [ NL. ] (Zool.) Same as Ginglymodi. [ 1913 Webster ]

n. [ Rhomb + root of Gr. gi`gnesqai to be born. ] (Zool.) A dicyemid which produces infusorialike embryos; -- opposed to nematogene. See Dicyemata. [ Written also rhombogen. ] [ 1913 Webster ]

a. (Geom. & Crystallog.) Related to the rhombohedron; presenting the form of a rhombohedron, or a form derivable from a rhombohedron; relating to a system of forms including the rhombohedron and scalenohedron. [ 1913 Webster ]

Rhombohedral iron ore (Min.) See Hematite. --
Rhombohedral system (Crystallog.), a division of the hexagonal system embracing the rhombohedron, scalenohedron, etc. [ 1913 Webster ]

a. (Geom. & Crystallog.) Rhombohedral. [ 1913 Webster ]

n. [ NL., fr. Gr. &unr_;&unr_;&unr_; rhomb + &unr_;&unr_;&unr_; seat, base. ] (Geom. & Crystallog.) A solid contained by six rhomboids; a parallelopiped. [ 1913 Webster ]

n. [ Gr. &unr_;&unr_;&unr_; rhomboidal; &unr_;&unr_;&unr_; rhomb + e'i^dos shape: cf. F. rhomboïde. ] (Geom.) An oblique-angled parallelogram like a rhomb, but having only the opposite sides equal, the length and with being different. [ 1913 Webster ]

a. Same as Rhomboidal. [ 1913 Webster ]