Where does “quinquenal” come from?
quinquenal (Spanish) comes from Latin quinquennalis, from Latin quinquennis, from Latin annus, from Proto-Italic atnos, from Proto-Indo-European h₂et-no-, from Proto-Indo-European h₂et- — grass.
quinquenal (Spanish): quinquennial, five-year
Ancestry of “quinquenal”, step by step