quadrennium

UK: /kwɒˈdrɛnɪəm/ US: (kwo dren′ē əm)

Inflections of 'quadrennium' (n):

quadrenniums

npl

quadrennia

npl

WordReference Random House Unabridged Dictionary of American English © 2026

quad•ren•ni•um  (kwo dren′ē əm), n., pl. quad•ren•ni•ums, quad•ren•ni•a 

(kwo dren′ē ə). 
1. a period of four years.

• Neo-Latin, alteration of Latin quadriennium, equivalent. to quadri- quadri- + -enn-, combining form of annus year (compare annual) + -ium -ium
• 1815–25

Collins Concise English Dictionary © HarperCollins Publishers::

quadrennium / kwɒˈdrɛnɪəm/ noun ( -niums, -nia / -nɪə/)

1. a period of four years

Also: quadriennium Etymology: 17th Century: from Latin quadriennium, from quadri- + annus year