Biannual / Biennial
Different meaningsBiannual means twice a year; biennial means every two years. For schedules, writing the frequency explicitly is often clearest.
Biannual
Use when
Something happens twice a year.
Example
“The committee conducts a biannual access review.”
Biennial
Use when
Something happens once every two years.
Example
“The biennial survey will next run in 2028.”
Quick check
biannual every two years, biennial twice a year
Usage note