So does “biweekly” mean twice a week or every two weeks? The answer is both. How ridiculous is that? On one hand, biweekly can mean twice in the same week. But it can also mean every other week. Who exactly was the head of word development when they came up with that chestnut?
But wait, it gets worse.
Bimonthly means twice a month. Or every other month.
Biannual means two times a year. Or every two years.
Biennial means every two years. Or two entire years.
The best part is what the dictionary says: Avoid the ambiguity by using alternative expressions. Better to say “it occurs every two months” or “it happens twice a year.”
So here’s what the dictionary is really saying. We’ve got these words. But they’re so confusing we don’t even recommend using them. Basically, they’re toxic. Best tossed onto the hazardous waste heap. Left out to die of their own stupidity.
Sounds about right to me.