1. Synonyms for Biyearly include semesterly, once every semester, once per semester, biannually, semiannually and semiyearly

2. Synonyms for Biannual include semiannual, six-monthly, twice-a-year, twice-yearly, half-yearly, semiyearly, every six months, biennial, periodic and regular

3. Synonyms for Biannually include semiannually, twice-a-year, twice-yearly, half-yearly, six-monthly, semiyearly, at six-monthly intervals, semesterly, once every semester and once per semester