Etymograph

English

semidecade

From semi- + decade.

Formed from semi- + decade

Proto-Indo-European *sem- ‘one’

Proto-Indo-European *sēmi ‘half’

English semi-

Proto-Indo-European *déḱm̥ ‘ten’

…

Ancient Greek δεκάς ‘the number ten’

Late Latin decās ‘(set of) ten’

Old French decade

Middle English decade

English decade

Today it means

noun A period of five years.

Sources

Sources: Wiktionary, “semidecade”. 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 / semidecade

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