Word Confusion: Biennial vs. Biannual

Word Confusion: Biennial vs. Biannual

  • Oct 19, 2023
  • 3 min read

Do you know when to use biennial vs. biannual? While the two words look and sound similar, there is a meaningful difference.

Some similar words are so familiar and so different in meaning that, should a client muddle them up, you will notice them right away. For instance, if an essay refers to Darwin’s theory of revolution, you can safely assume that this is an essay on The Origin of Species, not an examination of Darwin’s opinions on a classic Beatles song.

Some commonly confused words, however, can be tricky even for professional proofreaders. This is particularly true when it is not immediately obvious which of the two words is meant. You may be tempted to just leave things as they are and assume that the client is always right; but when you correct people for a living, this is a risky approach.

This post dives into the meaning of the words, biennial and biannual, and provides you with some examples of both so you will never get confused again.

Biennial and Biannual

The terms biennial and biannual have very similar spellings, meaning they look like they mean the same thing – but they don’t. Therefore, they are not, on any level, interchangeable. If you don’t pick up on the misuse of these words in a client’s document, it could be misleading.

But can you be sure which word a client meant? Not always. However, if ever you are unsure of a client’s meaning, you can leave a comment to check.

What Does Biennial Mean?

Biennial means once every two years; so, over a period of 730 days, it will happen only one time: 

Our family’s trip to the cabin is a biennial event because we can only rent it every second year.

A biennial plant takes two years to grow from seed, fully mature, and then die.

It is a biennial exhibit. One year it is here, the next it goes to the neighboring town, and then the following year it will come back.

What Does Biannual Mean?

Biannual means twice a year; so, within a period of 365 days, it will happen two times:

Our system is updated biannually, every January and July.

The sale is biannual, which is great because I love to stock up twice a year.

They host biannual parties for Christmas and Independence Day.

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