icosahedron

/(ˌ)aɪˌkoʊsəˈhiːdɹən/noun

icosahedron is a noun meaning “A polyhedron with twenty faces” (English Wiktionary, September 2026). It is spelled I-C-O-S-A-H-E-D-R-O-N, and it appears about once in every 14 million words in written English (wordfreq, 2021 data). The plural of icosahedron is icosahedra or icosahedrons.

What does icosahedron mean?

noun

1
A polyhedron with twenty faces.
2
A regular icosahedron: one of the Platonic solids, all of whose faces are regular (equilateral) triangles

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

How do you pronounce icosahedron?

/(ˌ)aɪˌkoʊsəˈhiːdɹən/
/(ˌ)aɪˌkɒsəˈhiːdɹən/
/(ˌ)aɪˌkɔsəˈhiːdɹən/

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: En-us-icosahedron.oga, Wikimedia Commons (author and licence on each file's page).

Forms of icosahedron

icosahedra plural
icosahedrons plural

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

How common is icosahedron?

Icosahedron appears about once in every 14 million words in written English, the 111,684th most frequent word form in the list.

icosahedron0.0010.010.11101001,00010,000

rarerper million words of written Englishmore common

Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).

Icosahedron in Spanish, French, German and Portuguese

In the sense a polyhedron:

Language	Words
French	icosaèdre
German	Ikosaeder, Zwanzigflächner, 20-Flächner
Portuguese	icosaedro
Spanish	icosaedro

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.

Where does icosahedron come from?

From Ancient Greek εἰκοσάεδρον (eikosáedron), from εἴκοσι (eíkosi, “twenty”) + ἕδρα (hédra, “face of a geometrical solid”). Equivalent to icosa- + -hedron.

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).