'Quinquennial' definitions:
Definition of 'Quinquennial'
- Quinquennial \Quin*quen"ni*al\, a. [L. quinquennalis and
quinquennis; quinque five + annus year. See Five, and cf.
Biennial.]
Occurring once in five years, or at the end of every five
years; also, lasting five years. A quinquennial event.
[1913 Webster]