- occurring every three years.
- lasting three years.
- a third anniversary.
- something that appears or occurs every three years.
- a period of three years; triennium.
Origin of triennial
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for triennially
The visits were repeated biennially till 1890, and then triennially.
Some unions meet annually, some biennially, some triennially, and a few determine by referendum when the convention is to meet.The Armies of Labor
Samuel P. Orth
- relating to, lasting for, or occurring every three years
- a third anniversary
- a triennial period, thing, or occurrence
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
Word Origin and History for triennially
Online Etymology Dictionary, © 2010 Douglas Harper