adjective / noun
biennial
by-EN-ee-ul/baɪˈeniəl/
Covering or completing a cycle of two years.
The trophy's biennial appearance leaves the intervening years empty.

Etymology
The pieces describe a two-year period. The adjective first meant lasting two years, then came to describe something recurring at two-year intervals.
In context
every two years it's a biennial charge
More examples
- Parsley is commonly grown as a biennial.
- The committee publishes a biennial report.
- These biennials usually flower in their second year.
Forms
biennial · biennials
Similar words
- annual
- Occurs every year or completes its life in one year.
- perennial
- A plant living for several years, or something enduring.