1. occurring twice a year
Usage: can be ambiguous – may also mean every two years
2. occurring every two years
Usage: can be ambiguous – may also mean twice a year

1. twice a year
Usage: can be ambiguous – may also mean every two years
2. every two years
Usage: can be ambiguous – may also mean twice a year

Examples

• The company holds biyearly meetings in June and December.
• Our biyearly budget review helps us stay on track.
• The magazine is published biyearly.
• They visit their grandparents biyearly.
• The conference occurs biyearly, alternating between odd and even years.
• We receive biyearly reports from the committee.