prettygoodword | quotennial

quotennial (kwoh-TEN-ee-uhl) - adj., (rare) happening every year, yearly, annual.

Or possibly, according to the other dictionary that has it, "of how many years (implying a long time)" -- so not only rare but probably also obsolete. Enough so, that frankly I can't see myself using it. So why run it? Because there's a closely related word that's relatively common: quotidian, meaning happening every day, and by extension, commonplace -- and that makes it a pretty good word in my book. Or my blog, anyway. Taken from Latin, from quot-, combining form of quod, how many + annus, year.

---L.