Etymograph

English

duality

Duality comes from Latin duālis ‘dual’, from duo ‘two’, and ultimately from Proto-Indo-European *dwóh₁.

  1. Proto-Indo-Europeanc. 4500–2500 BCE*dwóh₁1‘two’reconstructed
  2. Proto-Italicc. 1500–700 BCE*duō1‘two’reconstructed
  3. Latinc. 75 BCE–200 CEduo1‘two’
  4. Latinc. 75 BCE–200 CEduālis2‘dual’
  5. Latinc. 75 BCE–200 CEduālitās3
  6. Englishtodayduality3

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, Latin dualis
  2. 2 Wiktionary, Latin dualitas
  3. 3 Wiktionary, English duality

Lineage

  1. Proto-Indo-Europeanc. 4500–2500 BCE*dwóh₁Wiktionary, Latin dualis‘two’reconstructed
  2. Proto-Italicc. 1500–700 BCE*duōWiktionary, Latin dualis‘two’reconstructed
  3. Latinc. 75 BCE–200 CEduoWiktionary, Latin dualis‘two’
  4. Latinc. 75 BCE–200 CEduālisWiktionary, Latin dualitas‘dual’
  5. Latinc. 75 BCE–200 CEduālitāsWiktionary, English duality
  6. EnglishtodaydualityWiktionary, English duality

Linked words

through Proto-Indo-European *dwóh₁ ‘two’

two, doubt, vice, defeat, twin, binary, vicious, diplomacy, twain, bis, disparate, biceps, twig, binocular, betwixt, 21 more

through Proto-Italic *duō ‘two’

duet, 2 more

through Latin duo ‘two’

duo, dubious, deuce, bes, 1 more

Today it means

noun The quality of containing or comprising two often opposed parts or aspects.

Sources

Sources: Wiktionary, “duality”; the older steps come from the Wiktionary entries for Latin dualis, Latin dualitas. 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 *dwóh₁ / duality

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