triennial

[ trahy-en-ee-uh l ]
/ traɪˈɛn i əl /

adjective

occurring every three years.
lasting three years.

noun

a third anniversary.
something that appears or occurs every three years.
a period of three years; triennium.

RELATED WORDS

Origin of triennial

First recorded in 1555–65; trienni(um) + -al1

Related forms

tri·en·ni·al·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for triennial

British Dictionary definitions for triennial

triennial

/ (traɪˈɛnɪəl) /

adjective

relating to, lasting for, or occurring every three years

noun

a third anniversary
a triennial period, thing, or occurrence

Derived Forms

triennially, adverb

Word Origin for triennial

C17: from Latin triennium
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012