How congressional elections are held

• Every other year
• How often the Olympic Games occur

WordNet Word definitions in WordNet
adv. every two years; "this festival takes places biennially" [syn: biyearly ]

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Biennially \Bi*en"ni*al*ly\, adv. Once in two years.

Wiktionary Word definitions in Wiktionary
adv. Taking place every two years