quinquennium

• quinquennie

From Latin quīnquennium, from quinquennis (“5-year”) + -ium (suffix forming abstract nouns).

• (General American) IPA^(key): /kwɪŋˈkwɛniəm/
• (Received Pronunciation) IPA^(key): /kwɪŋˈkwɛnɪəm/, /kwɪnˈkwɛnɪəm/

quinquennium (plural quinquenniums or quinquennia)

1. A period of five years.

   Coordinate terms: annum, biennium, triennium, quadrennium, sexennium, septennium, octennium, novennium, decennium, vicennium, tricennium, centennium, quincentennium, millennium, decamillennium, centimillennium, millionennium

   During the quinquennium from 1991 to 1995, infant mortality increased.

The Roman usage of the term counted inclusively so that quinquennia were 4 year cycles. This is not usually intended in English but may occur in translations of classical texts.

Pentad or the neologism quintade are sometimes used when one wishes to specify the first and second halves of calendrical decades. Lustrum and luster are particularly used for the 5 year periods of the Roman censuses, after the purification ritual that usually followed the count.

• quinquennial, quinquennal, quinquenniad, quintennium, pentad, quintade, lustrum, luster

• See Thesaurus:quintet

• (adj.): quinquennial, quinquennal, quintennial

• “quinquennium, n.”, in OED Online ⁠, Oxford, Oxfordshire: Oxford University Press, 2022.

• (Classical Latin) IPA^(key): /kʷiːnˈkʷen.ni.um/,
• (modern Italianate Ecclesiastical) IPA^(key): /kwinˈkwen.ni.um/,

quīnquennium

1. genitive masculine/feminine/neuter plural of quīnquennis

From quīnquennis (“5-year”) +‎ -ium (“-ium: forming abstract nouns”), from quīnque (“five”) + annus (“year”) + -is (suffix forming compound adjectives).

quīnquennium n (genitive quīnquenniī or quīnquennī); second declension

1. A period of five years.
2. A five-year term of office.

Second-declension noun (neuter).

¹Found in older Latin (until the Augustan Age).

• “quinquennium”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “quinquennium”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• quinquennium in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.