Just How Frequently Is That?
Bi–
H.W. Fowler refers in Modern English Usage to the ‘misshapen brood’ of bi– words that are used to describe the frequency of intervals: biannual, bi-monthly, bi-weekly and the like.
The problem with them is that they are ambiguous: bi-weekly, for example, can mean either twice a week or every two weeks. At least a biennial (like the Biennale art exhibition held in Venice) is always held every two years, not twice in one.
Careful drafters of contracts will obviously want to make things perfectly clear, especially when dealing with dates of payment obligations and …