noun · 2 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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tĕtrəhē'drən
/ˌtɛtɹəˈhiːdɹən/
US:Recorded audio is listed in the source snapshot.
UK:Recorded audio is listed in the source snapshot.
rhymes with -iːdɹən
CMU ARPABET:T EH2 T R AH0 HH IY1 D R AH0 N
Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.
1
noun
Meaning 1
A polyhedron with four faces; the regular tetrahedron, the faces of which are equal equilateral triangles, is one of the Platonic solids.
Definition source: English Wiktionary via Wiktextract
Topics: geometry, mathematics, sciences
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
2
noun
Meaning 2
any polyhedron having four plane faces
Definition source: Princeton WordNet 3.0
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
Broader terms: polyhedron
History
Etymology
From Ancient Greek τετράεδρον (tetráedron, “triangle-based pyramid”), from τετράεδρος (tetráedros), from τετράς (tetrás, “four”) + ἕδρα (hédra, “seat”). By surface analysis, tetra- + -hedron.
Across languages
Translations
48 source translations are retained for this English entry.