The prefix bi derives from the latin bis, meaning "twice." Terms such as bimonthly, meaning once every two months, and biweekly, meaning every two weeks, are so defined in the dictionary, but suggest dual meanings. The secondary definition of bimonthly is, and is designated as loosely used in my dictionary, twice a month. In speaking of occurrences cycled in weeks or parts of weeks, I prefer "semiweekly" and the British term "fortnightly" for clarity of meaning. I wonder if there is something similar to use when referring to bimonthly events? I started to say, "...when referring to monthly cycles", but that's a whole 'nother subject.