Definitions
from Wiktionary, Creative Commons Attribution/ShareAlike License
 n. A rhombus
from the GNU version of the Collaborative International Dictionary of English
 n. 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.
 n. A rhombohedron.
from The Century Dictionary and Cyclopedia
 n. In geometry, an obliqueangled equilateral parallelogram; a quadrilateral figure whose sides are equal, and the opposite sides parallel, but the angles unequal, two being obtuse and two acute.
 n. In crystallography, a solid bounded by six equal and similar rhombic planes; a rhombohedron.
 n. In zoology, a pair of semirhombs forming a rhombic figure, as certain plates of cystic crinoids.
 n. A material circle.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
 n. a parallelogram with four equal sides; an obliqueangled equilateral parallelogram
Etymologies
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Examples

If the length of the sides of a parallelogram are all equal and the angles are not right angles, as in Figure 68, it is called a rhomb, rhombus or diamond.

Anonymous said ... some people say that your brain is a product if i bought it today i would take it back tomorrow so many defects and faults sometimes i wish i didnt need one at all  i hate my brain  frenzal rhomb say it best n straight to the point!!

Thus saving the Sun his labour, and the 'primum mobile,' 'that swift nocturnal and diurnal rhomb,' which carried all the lower spheres along with it, and brought about the change of day and night.

_ Calcium carbonate crystallizes in the form of rhombshaped crystals which belong to the hexagonal system.

On rotating this rhomb of spar, one of these marks is seen to revolve round the other, which remains stationary, the moving mark passing further from the centre in places.

He showed how to obtain and detect circularly polarized light by means of his rhomb.
The Catholic Encyclopedia, Volume 6: Fathers of the ChurchGregory XI

The Chinese and Tartar mandarins who accompanied them hindered them exceedingly; they had orders not to let the Fathers go where they would, ... and would never allow them sufficient time for observation of meridians, the measurement of roads, the variation of the needle (magnetic needle), the rhomb, and the estimation of positions from these elements.

A studded door stood ajar, and through the gap, from a guiding beacon of infamy, fell a rhomb of yellow light, suddenly obscured by a squat female figure when the steps of the

When, for example, in the demonstration of the theorem of Pythagoras, children handle the various pieces of the metal insets, they should start from the point at which they become aware that a rectangle is equal to the rhomb, and

Often as this rhombline must have been noticed, no explanation of it has ever, to my knowledge, been given.
reesetee commented on the word rhomb
See also rhumb.
October 14, 2008
chained_bear commented on the word rhomb
Usage on loxodromics.
October 14, 2008