I got a notice from my vet that my dog was due for a biannual procedure. It’s actually done every six months, so I finally suggested maybe they should call it a semiannual procedure. No, the office manager said. They looked it up years ago, and biannual means twice a year. Now let’s see. Semi- means half. Bi- means two. Logically, then, semiannual ought to refer to half a year and biannual ought to mean two years. But we’re dealing with the English language here.