English
dekad
Dekad comes from Ancient Greek δεκάς ‘group of ten’, and goes back to Proto-Indo-European *déḱm̥.
- Proto-Indo-Europeanc. 4500–2500 BCE*déḱm̥1‘ten’reconstructed
- Proto-Hellenicc. 2200–1600 BCE*dékə1‘ten’reconstructed
- Ancient Greekc. 800–300 BCEδέκᾰ2‘ten’
- Ancient Greekc. 800–300 BCEδεκάς3dekás‘group of ten’
- Englishearliest quotation 2022dekad3
attested reconstructed ? uncertain or disputed deepest recorded ancestor
- 1 Wiktionary, Ancient Greek δέκα
- 2 Wiktionary, Ancient Greek δεκάς
- 3 Wiktionary, English dekad
- Earliest quotation in Wiktionary’s entry: 2022, Africa InterTropical Front (ITF): “Figure 1 displays the current position of the ITF…”.
Lineage
- Proto-Indo-Europeanc. 4500–2500 BCE*déḱm̥Wiktionary, Ancient Greek δέκα‘ten’reconstructed
- Proto-Hellenicc. 2200–1600 BCE*dékəWiktionary, Ancient Greek δέκα‘ten’reconstructed
- Ancient Greekc. 800–300 BCEδέκᾰWiktionary, Ancient Greek δεκάς‘ten’
- Ancient Greekc. 800–300 BCEδεκάςWiktionary, English dekaddekás‘group of ten’
- Englishearliest quotation 2022dekadWiktionary, English dekad. Earliest quotation in Wiktionary’s entry: 2022, Africa InterTropical Front (ITF): “Figure 1 displays the current position of the ITF…”
Equivalent to deka- + -ad
Linked words
through Proto-Indo-European *déḱm̥ ‘ten’
ten, century, cent, hundred, dick, dozen, dean, sen, den, diner, hectare, decimal, tenfold, denier, dwt, doyen, deni, 49 more
through Ancient Greek δεκάς ‘group of ten’
Today it means
noun Ten days, especially of rainfall. Generally identified as dekad 1: 1ˢᵗ-10ᵗʰ, dekad 2: 11ᵗʰ-20ᵗʰ, and dekad 3: 21ˢᵗ-last day of each month.
Sources
Sources: Wiktionary, “dekad”; the older steps come from the Wiktionary entries for Ancient Greek δέκα, Ancient Greek δεκάς. 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 *déḱm̥ / dekad