Do you know the difference between “biannual” and “biennial”? Or is there a difference? And where does “semiannual” fit in? (Cue the Jeopardy music)
This is another one that trips up native speakers. A lot of folks don’t realize that “biannual” and “biennial” are two different words with two different meanings.
- “Biannual” means happening two times a year. “Semiannual” actually means the same thing.
- “Biennial,” on the other hand, has the same “bi” prefix, but means “once every two years.” It’s rare, but when someone is looking for the right word in this situation, “biannual” just won’t do. Precision and correct spelling are essential.
Some people like to keep it safe and avoid the “biannual” vs. “biennial” confusion by staying away from “biannual” all together. “Semiannual” will do just fine in its place in all cases.
The prefixes seem confusing, but don’t let them trip you up.
- “Bi-” means two. Think “bicycle,” two wheels, and bipod, two legs.
- “Semi-” on the other hand means “half.” Think “semi-circle,” half of a circle, or “semi-truck,” a truck whose trailer cannot move without the other half (the engine).
So “semi-annual” is twice a year, breaking the year into halves, and biennial is once every two years. The same logic follows for semi-weekly, twice a week, and bi-weekly, once every two weeks.
I knew one writer who kept this straight by remembering Victoria’s Secret has a semi-annual sale. What business would survive off a big sale every two years? Throw in supermodels in their underwear, and maybe Victoria’s Secret would do just fine, but that’s beside the point, right?
Writing Tip 204.1: “Bimonthly” is a little linguistic rebel with two definitions. It can mean either two times a month or once every two months. For example, I have a bimonthly writing and editing tips newsletter, that I email out once every two months, but maybe you receive a bimonthly update two times a month from your favorite online store. Both usages are correct.
“Bimonthly” is a bit tricky and a little bit annoying, but it is what it is. And these are the details we need to teach ourselves.
Happy writing, everyone!
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