Standard Lemma guide

octadecagon

noun · 1 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

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1

noun

Meaning 1

A polygon with 18 sides and 18 vertices.

Definition source: English Wiktionary via Wiktextract

Usage: rare

Topics: geometry, mathematics, sciences

Examples

  • A regular octadecagon cannot be constructed using a compass and straightedge.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

History

Etymology

From octadeca- + -gon.

Across languages

Translations

35 source translations are retained for this English entry.

  • Belarusian: васемнаццацікутнік (vasjemnaccacikutnik) — geometry
  • Bulgarian: осемнадесетоъгълник (osemnadesetoǎgǎlnik) — geometry
  • Catalan: octodecàgon — geometry
  • Chinese Mandarin: 十八邊形 /十八边形 (shíbā biānxíng) — geometry
  • Czech: osmnáctiúhelník — geometry
  • Dutch: achttienhoek — geometry
  • East Frisian Low German: achttainkâant — geometry
  • Esperanto: dekoklatero — geometry
  • Finnish: 18-kulmio (kahdeksantoistakulmio) — geometry
  • French: octadécagone — geometry
  • North Frisian: Achtainhuk — geometry
  • Saterland Frisian: Achttienkaant — geometry
  • West-Frisian: achttjinhoek — geometry
  • West-Frisian: achttsjinhoek — geometry
  • Galician: octodecágono — geometry
  • Georgian: თვრამეტკუთხედი (tvrameṭḳutxedi) — geometry
  • German: Achtzehneck — geometry
  • Greek: δεκαοκτάγωνο (dekaoktágono) — geometry
  • Hungarian: tizennyolcszög — geometry
  • Italian: ottadecagono — geometry
  • Japanese: 十八角形 (jūhachikakukei) — geometry
  • Korean: 십팔각형 (sip'palgakhyeong) — geometry
  • Macedonian: осумнаесетаголник (osumnaesetagolnik) — geometry
  • Polish: osiemnastokąt — geometry
  • Portuguese: octodecágono — geometry
  • Romanian: octodecagon — geometry
  • Russian: восемнадцатиугольник (vosemnadcatiugolʹnik) — geometry
  • Serbo-Croatian: осамнаестоугао — geometry
  • Serbo-Croatian: osamnaestougao — geometry
  • Slovene: osemnajstkotnik — geometry
  • Spanish: octodecágono — geometry
  • Swedish: oktadekagon — geometry
  • Thai: รูปสิบแปดเหลี่ยม — geometry
  • Turkish: onsekizgen — geometry
  • Ukrainian: вісімнадцятикутник (visimnadcjatykutnyk) — geometry