Biannual / biennial April 14, 2023 by styleguide Biannual means twice a year and is a synonym for “semiannual.” Biennial means every two years. Categories: StyleRelated Postswide / -wideApril 18, 2023yearsApril 18, 2023RACE-RELATED AND ETHNIC REFERENCESApril 18, 2023