from Wiktionary, Creative Commons Attribution/Share-Alike License
- adv. Taking place every two years
from the GNU version of the Collaborative International Dictionary of English
- adv. Once in two years.
from The Century Dictionary and Cyclopedia
- Once in two years; at the return of two years.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adv. every two years
biennial + -ly (Wiktionary)