Used when describing events that occur with a two-year gap, not annually. The international summit is a biennial event, not an annual one.
Pro Tip 2/3
Non-Yearly Plans
Helpful for planning or discussing occurrences that are not part of a yearly schedule. The committee plans to revise the guidelines on a biennial basis.
Pro Tip 3/3
Official Occasions
Commonly refers to official, governmental, or formal events and activities. The biennial budget review draws a lot of media attention.