# rhombus
## English
### Etymology

Learned borrowing from Latin rhombus, from Ancient Greek ῥόμβος (rhómbos, “rhombus, spinning top”). Doublet of rhomb and rhumb.

### Pronunciation

* (UK) IPA: /ˈɹɒmbəs/
* (US) IPA: /ˈɹɑːmbəs/
* Audio (General Australian):(file)

### Noun

rhombus (plural rhombi or rhombuses)
* (geometry) A parallelogram having all sides of equal length. [from 16th c.]
** The rhombus diamond, as one of the suits seen in a deck of playing cards ( or ).
* In early Greek religion, an instrument whirled on the end of a string similar to a bullroarer.
** 1936, Rollo Ahmed, The Black Art, London: Long, page 58:The Greeks also used an instrument called a rhombus, or witches' wheel. As the wheel spun round, it was thought that influence was gained over certain people or circumstances.
* (zoology, now rare) Any of several flatfishes, including the brill and turbot, once considered part of the genus Rhombus, now in Scophthalmus. [from 16th c.]
** 1638, Thomas Herbert, Some Yeares Travels, section I:the greedy Tuberon or Shark arm'd with a double row of venemous teeth pursues them, directed by a little Rhombus, Musculus or pilot-fish that scuds to and fro to bring intelligence [...].
* (zoology, archaic) Snails, now in genus Conus or family Conidae.

#### Synonyms

* (geometry): diamond (not in technical use), rhomb

#### Hyponyms

* (geometry): lozenge (if not square)

#### Holonyms

* (geometry): rhombohedron

#### Derived terms

* rhombus star

#### Related terms

* rhombic
* rhomboid

#### Translations
### References

* “rhombus”, in OneLook Dictionary Search.
* William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “rhombus”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC.

## Latin
### Alternative forms

* rombus, rumbus (Medieval Latin)

### Etymology

From Ancient Greek ῥόμβος (rhómbos, “rhombus, spinning top”), from ῥέμβω (rhémbō, “I turn around”).

### Pronunciation

* (Classical Latin) IPA: /ˈrom.bus/, [ˈrɔmbʊs̠]
* (modern Italianate Ecclesiastical) IPA: /ˈrom.bus/, [ˈrɔmbus]

### Noun

rhombus m (genitive rhombī); second declension
* rhombus (geometry)
* flatfish
* a magician's circle
* (Medieval Latin) sturgeon
    Synonym: sturiō
    Hyponym: carrocō

#### Declension

Second-declension noun.

#### Descendants

* Catalan: rom
* Italian: rombo
* Portuguese: rumo
* Spanish: rumbo, romo
** → English: rhumb
* Sicilian: rummu
Borrowings
* → Albanian: romb
* → Azerbaijani: romb
* → Catalan: rombe
* → Danish: rombe
* → English: rhombus, rhomb
* → French: rhombe
* → Galician: rombo
* → Georgian: რომბი (rombi)
* → German: Rhombus
** → Estonian: romb
* → Hungarian: rombusz
* → Latvian: rombs
* → Lithuanian: rombas
* → Macedonian: ромб (romb)
* → Norwegian: rombe
* → Polish: romb
* → Portuguese: rombo
* → Romanian: romb
* → Russian: ромб (romb)
** → Kazakh: ромб (romb)
* → Serbo-Croatian: romb / ромб
* → Slovene: romb
* → Spanish: rombo
* → Swedish: romb
* → Ukrainian: ромб (romb)

### References

* “rhombus”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
* “rhombus”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
* "rhombus", in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
* rhombus in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
* “rhombus”, in Harry Thurston Peck, editor (1898), Harper's Dictionary of Classical Antiquities, New York: Harper & Brothers
* “rhombus”, in William Smith et al., editor (1890), A Dictionary of Greek and Roman Antiquities, London: William Wayte. G. E. Marindin