decennalia

• Decennalia

From Latin decennālia, from decennium (“10-year period”) + -ālia (“-alia: forming the names of festivals”), from decennis (“10-year”) + -ium (“-ium: forming abstract nouns”). Equivalent to decennium +‎ -alia.

decennalia (plural decennalia or decennalias)

1. (historical) The festival and religious rituals celebrating a Roman emperor's 10th year of rule.
   • 1915, Arthur Evans, "Notes on the Coinage and Silver Currency in Roman Britain from Valentinian I to Constantine III", Numismatic Chronicle..., 4th Ser., Vol. 15, p. 436:

     Seven pieces celebrate the Decennalia of Arcadius, which were due on Jan. 15, 393.

   • 2005, Jakob Munk Højte, Roman Imperial Statue Bases from Augustus to Commodus, p. 157:

     The exact timing of the tenth and twentieth anniversaries, the decennalia and the vicennalia, has already been discussed at length. The most straightforward solution, that it took place on the emperor's dies imperii ten years after the accession, has its adherents. However, a date earlier in the year, perhaps even the day of the beginning of the tenth year, may also be considered—at least in the second century AD.

   • 2012, Gary Forsythe, "Magna Mater and the Taurobolium", Time in Roman Religion, p. 111:

     As a chronological list of Roman emperors makes clear, several rulers reign long enough to enjoy their decennalia, but relatively few were fortunate enough to celebrate their vicennalia, their twentieth imperial anniversary; and from the second century onwards Constantine alone ruled long enough to celebrate a tricennalia.

• decennial, decennials

• jubilee

• quinquennalia, quindecennalia, vicennalia, tricennalia

• (Classical) IPA^(key): /de.kenˈnaː.li.a/, [d̪ɛkɛnˈnäːlʲiä]
• (modern Italianate Ecclesiastical) IPA^(key): /de.t͡ʃenˈna.li.a/, [d̪et͡ʃenˈnäːliä]

decennālia

1. nominative/accusative/vocative neuter plural of decennālis

The Decennalia Base in the Forum, Rome

A siliqua commemorating the decennalia of the emperor Julian

From decennium (“10-year period”) +‎ -ālia (“-alia: forming the names of festivals”), from decennis (“10-year”) + -ium (“-ium: forming abstract nouns”), from deciēs (“ten times”) + annus (“year”) + -is (“forming compound adjectives”).

decennālia n pl (genitive decennālium or decennāliōrum); third declension

1. (historical) decennalia, the festival and religious rituals celebrating a Roman emperor's 10th year of rule.

   decennalia imperatorum

   10th anniversary of the emperors

Third-declension noun (neuter, “pure” i-stem), plural only.

• prīmī decennālēs, decennālia prīma

• quinquennalia, quindecennalia, vicennalia, tricennalia

• English: decennalia, decennial
• Italian: decennale