Tetrad
/ˈtɛt.ræd/noun
A group or set of four.
Did you know?The root behind tetrad also gave us words like tetrahedron and tetrachord, showing how ancient Greek used “four” as a building block for geometry, music, and cosmic order.
Etymological Timeline
Proto-Indo-European
PIE
*kʷetwor-
“four”
Ancient Greek
GR
τέτρας (tetras)
“a group of four”
Late Latin
Latin
tetrad-
“a set of four”
16th Century
English
tetrade
“a group of four”
Modern English
English
tetrad
“a group or set of four”
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