a. rare–0. [f. L. trīcenni-um period of thirty years (f. triciēs thirty times + annus year) + -AL.] Of or belonging to thirty years.
1656. Blount, Glossogr., Tricennial, of thirty or thrice ten years.
1731. Bailey, Tricennial, belonging to the Term of 30 Years.
1864. Webster, Tricennial, of, pertaining to, or consisting of, thirty years; occurring once in every thirty years.
