Etymograph

English

tetractys

Tetractys comes from Ancient Greek τετρακτύς ‘the sum of the first four numbers, i.e. 10 (=…’, from τετράς ‘the fourth day of the month’, and ultimately from Proto-Indo-European *kʷetwóres ‘four’.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*kʷetwóres1‘four’reconstructed
  2. Ancient Greekc. 800–300 BCEτετράς2‘the fourth day of the month’
  3. Ancient Greekc. 800–300 BCEτετρακτύς3tetraktús‘the sum of the first four numbers, i.e. 10 (= 1+2+3+4)’
  4. Englishearliest quotation 2009tetractys3

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Ancient Greek τετράς
  2. 2 Wiktionary, Ancient Greek τετρακτύς
  3. 3 Wiktionary, English tetractys
  4. Earliest quotation in Wiktionary’s entry: 2009, Cintra Wilson, Riches at Rainbow’s End: “ON the subway home, I noticed that the tattoo-esque…”.

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*kʷetwóresWiktionary, Ancient Greek τετράς‘four’reconstructed
  2. Ancient Greekc. 800–300 BCEτετράςWiktionary, Ancient Greek τετρακτύς‘the fourth day of the month’
  3. Ancient Greekc. 800–300 BCEτετρακτύςWiktionary, English tetractystetraktús‘the sum of the first four numbers, i.e. 10 (= 1+2+3+4)’
  4. Englishearliest quotation 2009tetractysWiktionary, English tetractys. Earliest quotation in Wiktionary’s entry: 2009, Cintra Wilson, Riches at Rainbow’s End: “ON the subway home, I noticed that the tattoo-esque…”

Linked words

through Proto-Indo-European *kʷetwóres ‘four’

fourth, quarry, cater, kern, farthing, carillon, quatre, quire, cuatro, ferd, quatrain, 18 more

Today it means

noun A triangular figure consisting of ten points arranged in four rows, representing the fourth triangular number and having mystical significance to the Pythagoreans.

Sources

Sources: Wiktionary, “tetractys”; the older steps come from the Wiktionary entries for Ancient Greek τετράς, Ancient Greek τετρακτύς. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.

Etymograph / Proto-Indo-European *kʷetwóres / tetractys

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