triennial

About 0.26 uses per million words.

Meaning

1. adjective Happening every three years.

   triennial elections

2. adjective Lasting for three years.

   triennial parliaments; a triennial reign

3. noun A third anniversary.
4. noun A plant that requires three years to complete its life-cycle.

Similar words

tercentennial tercentenary biennial quarterly triennium triple tripartite trilateral triangular cyclical

Often followed by

parliaments act bill convention meeting conference elections report election

Word family

triennially triennials