rhombus

[rom-buh s] /ˈrɒm bəs/
noun, plural rhombuses, rhombi
[rom-bahy] /ˈrɒm baɪ/ (Show IPA)
1.
an oblique-angled equilateral parallelogram; any equilateral parallelogram except a square.
2.
an equilateral parallelogram, including the square as a special case.
3.
a rhombohedron.
Origin
1560-70; < Latin < Greek rhómbos anything that may be spun around, derivative of rhémbein to revolve
Examples from the web for rhombus
  • D is a rhombus because all four sides are congruent.
  • The rhombus has two acute angles, four angles, and equal sides and is a parallelogram.
British Dictionary definitions for rhombus

rhombus

/ˈrɒmbəs/
noun (pl) -buses, -bi (-baɪ)
1.
an oblique-angled parallelogram having four equal sides Also called rhomb Compare square (sense 1)
Word Origin
C16: from Greek rhombos something that spins; related to rhembein to whirl
Word Origin and History for rhombus
n.

1560s, from Late Latin rhombus, from Greek rhombos "rhombus, rhomb, lozenge; spinning top, maghic wheel used by sorcerers; a spinning motion," from rhembesthai "to spin, whirl," from PIE *wrembh-, from *werbh- "to turn, twist, bend" (cf. Old English weorpan "to throw away"), from root *wer- (3) "to turn, bend" (see versus).

rhombus in Science
rhombus
  (rŏm'bəs)   
Plural rhombuses or rhombi (rŏm'bī)
A parallelogram with four equal sides; an equilateral parallelogram.

rhomboid, rhomboidal adjective