Tetrahedron
/ˌtɛtrəˈhiː.drən/noun
A solid geometric figure with four triangular faces.
Did you know?The second half comes from Greek *hedra* meaning “seat” or “base,” so a tetrahedron is basically a “four-seated” form in the language of ancient geometry.
Etymological Timeline
Ancient Greek
Greek
tetraedron
“a figure with four faces or bases”
Late Latin
Latin
tetraedrum
“a tetrahedral solid”
Middle French
Old French
tétraèdre
“a geometric solid with four faces”
16th Century
English
tetrahedron
“a solid figure with four triangular faces”
Modern English
English
tetrahedron
“a solid geometric figure with four triangular faces”
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