triannual

[trahy-an-yoo-uh l]
noun
  1. a triannual publication, contest, etc.
  2. triennial.

Origin of triannual

First recorded in 1630–40; tri- + annual
Related formstri·an·nu·al·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Word Origin and History for triannual
adj.

1630s, from tri- + annual. Related: Triannually.

Online Etymology Dictionary, © 2010 Douglas Harper