There are 2 main definitions of pentagon in English:

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pentagon1

Line breaks: penta|gon
Pronunciation: /ˈpɛntəɡ(ə)n
 
/

noun

A plane figure with five straight sides and five angles.
Example sentences
  • In the second case, if the convex polygon is a pentagon incorporating all five points, then any four of these points can be connected to form a quadrilateral.
  • This says that the most stable arrangement is a pentagon surrounded by five hexagons.
  • The hexagons, pentagons, and triangles that make up the biomes all have their own unique specification due to the irregular nature of the site.

Origin

late 16th century: via Latin from Greek pentagōnon, neuter (used as a noun) of pentagōnos 'five-angled'.

More
  • The Greek expertise in geometry means that many geometrical forms have Greek names. The five-sided pentagon is formed from penta ‘five’ and gonia ‘angle’, just as polygon (late 16th century) is formed from the word for ‘many’ plus -gon and diagonal (mid 16th century) with dia ‘through’. Penta is also found in words such as the mystic figures of the pentangle (Late Middle English), pentacle (late 16th century), and pentagram (mid 19th century), and in the pentathlon (early 17th century), once the original five events of leaping, running, discus-throwing, spear-throwing, and wrestling of ancient Greek and Roman games. Fifty is found in Pentecost (Old English) which came via ecclesiastical Latin from Greek pentēkostē (hēmera) ‘fiftieth (day)’. The Jewish festival of Shavuoth is held on the fiftieth day after the second day of Passover. The Christian festival is held on the seventh Sunday after Easter commemorating the descent of the Holy Spirit on the disciples as recorded in Acts 2.

Derivatives

pentagonal

1
Pronunciation: /-ˈtaɡ(ə)n(ə)l/
adjective
Example sentences
  • Ring compounds most often contain five or six atoms to form pentagonal or hexagonal structures.
  • This only occurs at the time when the pentagonal symmetry of the flower becomes visible and organ identity genes are expressed.
  • The Sergeant gave her a pentagonal shaped cabin slightly larger, slightly more comfortable than the one she had had downstairs, sporting retractable shelves which sprung out here and there to alter the shape of the room.

Words that rhyme with pentagon

hexagonheptagon

Definition of pentagon in:

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There are 2 main definitions of pentagon in English:

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Pentagon2

Line breaks: Penta|gon
Pronunciation: /ˈpɛntəɡ(ə)n
 
/
(the Pentagon)
1The pentagonal building serving as the headquarters of the US Department of Defense, near Washington DC. Part of the building was badly damaged in the terrorist attacks of 11 September 2001.
1.1The US Department of Defense: the Pentagon said that ten soldiers had been killed

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