noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   A polygon with twenty-one edges and twenty-one angles.

Synonyms

All synonyms

21-gon

Etymology

From Ancient Greek εἰκοσιέν (eikosién, “twenty-one”) + -gon, from εἴκοσι (eíkosi) (twenty) + ἕν (hén) (one).

Related phrases

twenty one

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.