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πεντάγωνον

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Etymology and origin of the Ancient Greek word πεντάγωνον

Confidence
Established
Formation
Derivation
First attested
1–200 Plutarch More words from the 1st century
Ultimate origin
Ancient Greek πεντάγωνος
Etymology tree
inherited borrowed derived
Ancient Greek πεντάγωνον (pentágōnon)
Latin pentagōnum
From the same root
English pentagon ← πεντάγωνον

Pronunciation

  • 5th-century BC Attic: /pen.tá.ɡɔː.non/[1]
  • 4th-century AD Koine: /penˈta.ɣo.non/[1]
  • 10th-century Byzantine: /penˈta.ɣo.non/[1]

Forms

πεντάγωνον (pentágōnon) n (genitive πεντᾰγώνου); second declension[1]

Etymology

It is the neuter of the adjective from Ancient Greek πεντάγωνος (pentágōnos, “five-angled”), used as a noun.[1][2][3] The adjective is a compound of πέντε (pénte, “five”) and γωνία (gōnía, “angle, corner”).[4][5]

Earliest recorded meaning

The adjective is found first in a fragment of Aristotle (4th century BC), meaning “pentagonal”;[2][6] the neuter noun, a pentagon, is found in Plutarch and Galen.[2][7]

Semantic evolution

In Greek mathematics the adjective qualified pentagonal numbers and bases, as in Nicomachus' Introduction to Arithmetic;[2] the noun named the plane figure with five angles.[2][8]

Late Latin took it as pentagonum, and English has pentagon from the 1560s, from French or Latin; the name of the United States military headquarters, finished in 1942, comes from the building's shape.[5] The Modern Greek word is πεντάγωνο (pentágono).[3]

Timeline

  • 4th century BC – A fragment of Aristotle has the adjective πεντάγωνος “pentagonal”.[2][6]
  • 1st–2nd century AD – Nicomachus speaks of pentagonal numbers and bases.[2][6]
  • 1st–2nd century AD – Plutarch uses the neuter as a noun for the pentagon.[2][6]
  • 2nd century AD – Galen uses the noun.[2][6]
  • 1560s – English takes pentagon from French or Late Latin.[5]

Meanings

Noun

  1. (geometry) A pentagon, a plane figure with five angles.[2][8][7]

Usage notes

The adjective πεντάγωνος, ον “pentagonal” is the base of the noun.[2]

References

  1. ^ a b c d e Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k Liddell, Henry George; Scott, Robert; Jones, Henry Stuart (1940), A Greek-English Lexicon, 9th ed., Oxford: Clarendon Press
  3. ^ a b Βικιλεξικό, the Greek Wiktionary, https://el.wiktionary.org
  4. ^ Köbler, Gerhard, Griechisch-deutsches Wörterbuch, online ed., https://www.koeblergerhard.de
  5. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  6. ^ a b c d e Rodríguez Adrados, Francisco, et al., eds. (1980–), Diccionario Griego-Español, Madrid: CSIC, http://dge.cchs.csic.es/xdge
  7. ^ a b Дворецкий, И. Х. (1958), Древнегреческо-русский словарь, Moscow: ГИС
  8. ^ a b Korinthios, J. (2025), Grande Dizionario Greco Classico: Greco–Italiano, digital ed., Milan: Hoepli
Cite this entry

“Πεντάγωνον.” Etymologically, 8 Nov. 2026, etymologically.com/grc/%CF%80%CE%B5%CE%BD%CF%84%CE%AC%CE%B3%CF%89%CE%BD%CE%BF%CE%BD. Accessed 8 Nov. 2026.

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