Biannual vs Biennial: What’s The Difference?

Do you get confused about biannual vs biennial events? Before you show up at the wrong time, consider this guide to these two commonly confused words.

Is the weekend festival in your town a biannual event or a biennial event? Like many words with similar spellings, these two are easily confused words, but they do not have the same meaning. Decoding the difference between biannual vs. biennial will make your writing stronger.

Thankfully, all it takes is a closer look at the definitions of these words to help you use them correctly in your English writing.

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Biannual Vs Biennial Meanings and Usage

Biannual vs biennial

So how can you tell the difference between biannual vs. biennial? Looking at the different meanings of these two words is a good starting point.

Biannual Definition

The word biannual means “occurring twice a year” according to the Merriam-Webster Dictionary. This meaning is fairly standard.

Here are some example sentences using biannual correctly:

  • The biannual meeting gave the CEOs a chance to connect and talk about their plans for the future.
  • The biannual film festival was a great opportunity for students to showcase their skills.
  • The biannual scholarship required the applicants to renew at the end of each semester so they could show their GPA.

Biannual Etymology 

Biannual comes from combining the prefix bi, which means twice, with the word annual, which means yearly. It first was seen in the English language in 1877.

Synonyms for Biannual

biannual vs biennial
Semiannual also means happening twice a year, usually every six months

Biannual does not have many synonyms, but semiannual is one. Semiannual also means happening twice a year, usually every six months.

Several words come from the word biannual or have similar meanings, though they are not true synonyms. The adverb biannually comes from the word. 

The words bimonthly and biweekly have a similar meaning, but with a different time frame attached to them. Bimonthly means twice a month, while biweekly means twice a week.

Biennial Definition

The dictionary says that the adjective biennial means “occurring every two years” or “continuing or lasting for two years.” This definition is distinct from biannual because it means every two years, rather than two times a year.

Here are some example sentences using biennial correctly:

  • The biennial elections allowed a new congress to take control.
  • The biennial state budget was difficult to balance.
  • Our family trip to New York City happens on a biennial basis on odd-numbered years.

Biennial Etymology

Biennial is an older word than biannual. It was first used in the 1500s. The word comes from the Latin word biennis, which is the prefix bi combined with the word annus, which means year. 

Even though this etymology is similar to biannual, the word has a different meaning. 

Synonyms for Biennial

Like biannual, biennial does not have synonyms. It does have some words that come from it, however. These include:

  • Biennially: This adverb refers to an action that happens every two years.
  • Biennium: This noun refers to a two-year period of time.

How to Remember the Difference

So how can you remember the difference between biannual and biennial? If you can relate the word “annual” to “year,” then you can remember that biannual means events that happen within the same year. You might also find our adverse vs. averse guide helpful.

A Final Word on Biannual vs. Biennial

Because their meanings are so similar and they sound somewhat similar, biannual and biennial are difficult to keep straight. However, they are distinct words with distinct meanings.

A biannual conference is something that happens two times a year, while a biennial conference happens every two years. Similarly, biennial flowers have a life cycle that has blooms every other year. Biannual plants do not exist, but annual plants are those that only grow for one season, then die off.

FAQs on Biannual vs. Biennial

What is the difference between biennial and biannual?

Biannual means an event or activity that happens two times in the same calendar year. Biennial is something that happens every two years.  

Is twice a year semiannual or biannual?

Both semiannual and biannual can mean something that happens twice a year. technically, semiannual events happen every six months, while biannual events can be spaced out differently, but the two words are practically synonyms.

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  • Nicole Harms has been writing professionally since 2006. She specializes in education content and real estate writing but enjoys a wide gamut of topics. Her goal is to connect with the reader in an engaging, but informative way. Her work has been featured on USA Today, and she ghostwrites for many high-profile companies. As a former teacher, she is passionate about both research and grammar, giving her clients the quality they demand in today's online marketing world.