decennial

English

A siliqua commemorating the decennial of the Roman emperor Julian

From Latin decennialis, from decennium (“10-year period”) + -ālis, from decennis (“10-year”) + -ium (“-ium”, suffix forming abstract nouns), from decem (“ten”) + annus (“year”) + -is (suffix forming compound adjectives).

decennial (plural decennials)

Synonym of decade, a ten-year period.
A tenth anniversary, particularly
1. (historical) Synonym of decennalia, the festival and religious ritual held in the 10th year of a Roman emperor's reign.
  - 2022, Martin Hallmannsecker, Roman Ionia..., p. 110:
    Roman coins mentioning the vota publica for Macrinus are RIC IV.1 5–13; on vota publica for the decennials and vicennials of emperors in the 2nd and 3rd c. ad, see Chastagnol 1984.

In reference to the Roman festival, sometimes used in the plural to match Latin decennalia and provide for the variety of events.

tenth anniversary of an event

decennial (not comparable)

Occurring every ten years