Bimonthly can also mean "every other week" if it's twice in a month, or it can mean “every other month.” ... Similarly, the adjective bimonthly is defined as "occurring every two months" AND as "occurring twice a month."

What is the word for twice per month?

2 : occurring twice a month : semimonthly. bimonthly.

Is twice a month biweekly or bimonthly?

So even though biweekly is universally understood to mean every two weeks, bimonthly can mean every two months or twice a month.