quadrennial

adj

1. (not-comparable)Happening every four years.

   “The quadrennial election of Chief Magistrate has passed off with less than the usual excitement.”

2. (not-comparable)Lasting for four years.

noun

1. A four-year period, a quadrennium.

   “International rowing's elite tend to think in terms of quadrennials — the four-year cycle between Olympic Games — but the addition of the light women's double to Olympic program prior to the 1996 Atlanta Games has also brought distinct eras to the event.”