triennial
noun
- an event occurring or being done every three years
adjective
- recurring every three years
- consisting of or lasting for three years
Wiktionary
Pronunciation: /tɹaɪˈɛni.əl/
adj
Etymology: From Latin triennium (“three-year period”), from tres (“three”) + annus (“year”). By surface analysis, tri- + -ennial.
- Happening every three years.
“triennial elections”
“They were constantly summoned to a triennial festival : and the most approved songs delivered at this assembly were ordered to be preserved in the custody of the king's historian or antiquary”
- Lasting for three years.
“triennial parliaments; a triennial reign”
“September 13 1621, James Howell. letter to Sir William Saint John Triennial Subsidies”
noun
Etymology: From Latin triennium (“three-year period”), from tres (“three”) + annus (“year”). By surface analysis, tri- + -ennial.
- A third anniversary.
- A plant that requires three years to complete its life-cycle.