tetrahedron
/ˌtɛtɹəˈhiːdɹən/noun
tetrahedron is a noun meaning “A polyhedron with four faces; the regular tetrahedron, the faces of which are equal equilateral triangles, is one of the Platonic solids” (English Wiktionary, September 2026). It is spelled T-E-T-R-A-H-E-D-R-O-N and has 4 syllables, and it appears about once in every 5 million words in written English (wordfreq, 2021 data). The plural of tetrahedron is tetrahedra or tetrahedrons.
What does tetrahedron mean?
noun
- 1
A polyhedron with four faces; the regular tetrahedron, the faces of which are equal equilateral triangles, is one of the Platonic solids.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
How do you pronounce tetrahedron?
- /ˌtɛtɹəˈhiːdɹən/
Tetrahedron has 4 syllables (counted from its American pronunciation in the CMU Pronouncing Dictionary).
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: LL-Q1860_(eng)-Vininn126-tetrahedron.wav, LL-Q1860_(eng)-Rho9998-tetrahedron.wav, Wikimedia Commons (author and licence on each file's page).
Forms of tetrahedron
- tetrahedra plural
- tetrahedrons plural
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
How common is tetrahedron?
Tetrahedron appears about once in every 5 million words in written English, the 66,686th most frequent word form in the list.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
Tetrahedron in Spanish, French, German and Portuguese
In the sense polyhedron:
| Language | Words |
|---|---|
| French | tétraèdre |
| German | Tetraeder, Vierflächner, 4-Flächner |
| Portuguese | tetraedro |
| Spanish | tetraedro |
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 tetrahedron come from?
From Ancient Greek τετράεδρον (tetráedron, “triangle-based pyramid”), from τετράεδρος (tetráedros), from τετράς (tetrás, “four”) + ἕδρα (hédra, “seat”). By surface analysis, tetra- + -hedron.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).