BIENNIALLY
biennially, biyearly
(adverb) every two years; “this festival takes places biennially”
Source: WordNet® 3.1
Etymology
Adverb
biennially (not comparable)
Taking place every two years
Synonyms
• biannually (see usage notes)
Source: Wiktionary
Bi*en"ni*al*ly, adv.
Definition: Once in two years.
BIENNIAL
Bi*en"ni*al, a. Etym: [L. biennalis and biennis, fr. biennium a space
of two years; bis twice + annus year. Cf. Annual.]
1. Happening, or taking place, once in two years; as, a biennial
election.
2. (Bot.)
Definition: Continuing for two years, and then perishing, as plants which
form roots and leaves the first year, and produce fruit the second.
Bi*en"ni*al, n.
1. Something which takes place or appears once in two years; esp. a
biennial examination.
2. (Bot.)
Definition: A plant which exists or lasts for two years.
Source: Webster’s Unabridged Dictionary 1913 Edition