In a meeting today, one of our board members discussed having a conference every two years. She kept calling it a biannual conference, while I thought to myself, "she really means biennial." Then I looked it up in my AHD and on dictionary.com. My dictionary only gave the definition of "twice yearly" or "semi-annually". However, some of the sites on dictionary.com said either twice yearly or every two years. Now--that isn't very precise is it? How do you use them?
By the way, this board member said, "Irregardless of whether we do the conference annually or biannually....." Grrrr!
The prefix bi- is problematic since in some words it means “occurring twice in a specified period of time” while in others in means “occurring once in two periods. In other words it can have either meaning (bimonthly, 1: occurring every two months or 2: occurring twice a month : SEMIMONTHLY; biweekly, 1 : occurring twice a week or 2: occurring every two weeks : FORTNIGHTLY - M-W)
Bill Bryson, in his excellent book, Bryson’s Dictionary of Troublesome Words (Broadway Books, 2002, previously published as Penguin Dictionary of Troublesome Words and Phrases by Penguin UK) says:
“Bimonthly, biweekly. and similar designations are almost always ambiguous. It is far better to say ‘every two months,’ ‘twice a month,’ etc., as appropriate.”
I wonder if the word purists would even find a distinction with semi-annual versus biannual. After all "semi" means half so semi-annual should mean every 6 months. Yet, biannual really only means twice a year. For example, I visit my dentist semi-annually (each July and December), but biannually I am in touch with my friend who lives in France. The latter example may refer to visits in June and August.
In a recent QT column, someone asked about the "biweekly" definition because of Dictionary.com. We have talked about "biannual" before. QT, with authority, said, "'Biweekly' is every two weeks. 'Semiweekly' is twice a week."
I don't think he is correct in that. In fact, I think more people say "biweekly" to mean twice a week than every two weeks. What would you say? I am thinking of e-mailing him about our thoughts.
Usage Note: Bimonthly and biweekly mean “once every two months” and “once every two weeks.” For “twice a month” and “twice a week,” the words semimonthly and semiweekly should be used. Since there is a great deal of confusion over the distinction, a writer is well advised to substitute expressions like every two months or twice a month where possible. However, each noun form has only one sense in the publishing world. Thus, a bimonthly is published every two months, and a biweekly every two weeks.
Source: The American Heritage® Dictionary of the English Language, Fourth Edition
Of course, you could go British on us and use fortnightly.
Interesting that you should mention "fortnightly," Tinman. I have been reading a lot of research reports lately, as I am preparing a systematic review. Many of these are from England. The last one I read talked about meeting "fortnightly" with the subjects, for a total of 15 meetings in a year.