quinquennium

noun

quin·​quen·​ni·​um kwin-ˈkwe-nē-əm 

kwiŋ-

plural quinquenniums or quinquennia kwin-ˈkwe-nē-ə 

kwiŋ-

: a period of five years

Word History

Etymology

Latin, from quinque five + annus year — more at five, annual

First Known Use

1621, in the meaning defined above