Biannual and semiannual can be used interchangeably; they both mean “twice a year.” But biennial describes something that occurs every two years.
If you regularly submit stories and poems to literary magazines twice a year, you have a biannual or semiannual submission plan. But if you don’t much care about publication credits and only submit your writing every two years, you have a biennial (and less effective) submission plan…and you may want to contact Writer’s Relief to jump-start your writing career!
Note: To avoid confusion between biannual and biennial, many writers prefer semiannual to describe an event that happens twice a year.
