Annual or Ennial?

Mar 13, 2020 | Posted by Jennifer


Back when I lived in Ohio, I spent much of March watching the weather. Typically at some point in the month, usually later than earlier, I could detect a subtle warming in the air. The breeze wouldn’t bite so hard. Clouds began to thin. Spring was near! I would stand at the kitchen sink and gaze out the window at a dormant backyard with its brown grass and barren flower beds. Soon it would be time for me to head out to purchase some colorful and cheery annuals to brighten the beds for the entire spring and summer seasons. Soon.

This scene planted in my brain as I was sitting at my tutoring table earlier this week. I was working with a student on learning word parts (morphology), and the word was “biannual.” “Bi,” I started, and he finished for me, “Bi means two, as in bicycle!”

“So biannual would mean … ,” I probed.

“Twice a year,” he answered.

We continued. “Triennial” appeared on the list. “Tri means three, but I’m not sure about this part,” he said, pointing to “ennial.”

He’s in good company. For many years I also hesitated, confused about whether “biennial” means twice a year or once every two years. Eventually I learned a trick that has stuck with me. Both “annual” and “ennial” come from the Latin root “annus,” which means “year.” The distinction comes from how the time period is measured. In the case of “biannual,” it means “occurring twice a year.”

“Biennial” has a slightly different meaning. It means “every two years” or “over the course of two years.” I italicized “ennial” and “every” to show the memory trigger. They both begin with the short vowel-e sound, which helps me to remember that “ennial” means “every.”

If you know your prefixes, you can combine “annual” and “ennial” into a broad list of words, some of which I describe below:

  • Perennial: “Per” means “through,” so perennials are plants that survive through the year; you don’t have to replant them each spring.
  • Biennial: “Bi-” means two, so this word could mean “occurring every other year,” or it could refer to a plant that takes two years to have a full life cycle.
  • Centennial: “Centi-” means one hundred, so a “centennial” would mean once every hundred years. It follows then that a “bicentennial” would mean once every two hundred years.
  • Triannual: “Tri-” means “three,” so this word would refer to something occurring three times within the span of a single year.
  • Sesquicentennial: This is a fun one! “Sesque” means “one and a half times more,” so a sesquicentennial would mean a 150-year anniversary.

It’s kind of funny how sitting at a table with a student at my side learning prefixes can draw me back to Ohio and March and flowers. It’s so serendipitous! As you expectantly await spring, I hope you find beautiful annuals to fill your barren garden plots and look forward to the revival of your perennials as well. Spring may seem to take its time to arrive, but I promise you, it’s just around the corner!


Jennifer Mauser has always loved reading and writing and received a B.A. in English from the University of Kansas in 1991. Once she and her husband had children, they decided to homeschool, and she put all her training to use in the home. In addition to homeschooling her children, Jennifer teaches IEW classes out of her home, coaches budding writers via email, and tutors students who struggle with dyslexia.

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