IPA: /kwəˈdrɛn.i.əl.i/
KK: /kwɑˈdrɛnɪəli/
Happening every four years.
The Olympic Games are held quadrennially, attracting athletes from around the world.
Quadrennially → It is formed from "quad-" (meaning four) and "annus" (meaning year) combined with the suffix "-ly" (meaning in a manner). The word "quadrennially" means occurring every four years.
Think of 'four' ('quad-') and 'year' ('annus') to remember that 'quadrennially' refers to something that happens every four years.
No commonly confused words.