On ‘Biweekly’ and ‘Bimonthly’: Sorry, not sorry

Merriam Webster:

What to Know

Biweekly and bimonthly can mean the same thing because of the prefix bi-, which here can mean “occurring every two” or “occurring twice in.” Therefore, biweekly can be “twice in a week” or “every other week.” Bimonthly can also mean “every other week” if it’s twice in a month, or it can mean “every other month.”

Look up the adjective biweekly in this dictionary and you will see it defined as “occurring every two weeks” AND as “occurring twice a week.” Similarly, the adjective bimonthly is defined as “occurring every two months” AND as “occurring twice a month.” 

For this, we are sorry. But we don’t mean “sorry” in the sense that we feel penitence; we are not to blame. We mean “sorry” in the sense that we feel a kind of sorrow aroused by circumstances beyond our control or power to repair.