triennial

From Latin triennium (“three-year period”), from tres (“three”) + annus (“year”). By surface analysis, tri- +‎ -ennial.

• IPA^(key): /tɹaɪˈɛniəl/

• Audio (Southern England)

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• Rhymes: -ɛniəl

triennial (not comparable)

1. Happening every three years.

   triennial elections

   • 1774-1781, Thomas Warton, History of English Poetry:

     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

2. Lasting for three years.

   triennial parliaments; a triennial reign

   • September 13 1621, James Howell. letter to Sir William Saint John

     Triennial Subsidies

• (rare): trieterical

• (noun): triennium

• triennially

triennial (plural triennials)

1. A third anniversary.
2. A plant that requires three years to complete its life-cycle.

• biennial
• triennium
• triannual