bi·​en·​ni·​al | \ (ˌ)bī-ˈe-nē-əl \

Definition of biennial

1 : occurring every two years a biennial celebration
2 : continuing or lasting for two years specifically, of a plant : growing vegetatively during the first year and fruiting and dying during the second Biennial herbs flower in their second year.

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Other Words from biennial

biennial noun
biennially \ (ˌ)bī-​ˈe-​nē-​ə-​lē \ adverb

What do bimonthly and biweekly mean?: Usage Guide

Many people are puzzled about bimonthly and biweekly, which are often ambiguous because they are formed from two different senses of bi-: "occurring every two" and "occurring two times." This ambiguity has been in existence for nearly a century and a half and cannot be eliminated by the dictionary. The chief difficulty is that many users of these words assume that others know exactly what they mean, and they do not bother to make their context clear. So if you need bimonthly or biweekly, you should leave some clues in your context to the sense of bi- you mean. And if you need the meaning "twice a," you can substitute semi- for bi-. Biannual and biennial are usually differentiated.

Did You Know?

Biennial conventions, celebrations, competitions, and sports events come every two years. Biennials are plants that live two years, bearing flowers and fruit only in the second year. (Carrots and sugar beets are two examples; since we're only interested in their roots, we don't wait another year to see their flower and fruit.) In contrast, semiannual means "twice a year". But no one can agree whether biweekly means "twice a week" or "every two weeks", and whether bimonthly means "twice a month" or "every two months". Maybe we should stop using both of them until we can decide.

Examples of biennial in a Sentence

The governor explained the biennial budget proposal.

Recent Examples on the Web

The home dedications, in honor of two of the sorority’s former international presidents, kicked off the sorority’s biennial conference being hosted in Houston July 6-12 at the George R. Brown Convention Center and several city hotels. Elizabeth Myong, Houston Chronicle, "AKA sorority sisters serve the Houston community," 7 July 2018 In July, the company, known for commercial jet engines, unveiled an electric vertical-takeoff-and-landing concept at the biennial Farnborough Air Show in England. Dan Neil, WSJ, "The First Flying-Car Review," 12 Sep. 2018 Monaco makes its biennial appearance—this race happens every other year; Formula E and the historic races alternate annually before the famed Formula 1 race takes the streets of this principality. Jonathan M. Gitlin, Ars Technica, "Formula E starts season 5 in Saudi Arabia with a faster electric race car," 14 Dec. 2018 This is perhaps a better fit for EA than anyone else, given the company’s focus on annual or biennial series like FIFA, Madden, and Battlefield where the majority of the player base migrates to each new release. Sam Byford, The Verge, "EA’s unlimited PC games subscription service launches next week," 27 July 2018 The Hammer Museum’s latest biennial brings together Los Angeles and two artists take on LAX. Carolina A. Miranda,, "Datebook: A beguiling biennial, photos of life near LAX and tributes to a mythic female ruler," 7 June 2018 The Director of Athletics for the Clear Creek Independent School District didn't anticipate much jostling within the ranks of District 24-6A in the University Interscholastic League's biennial realignment and her suspicions were confirmed. Ted Dunnam, Houston Chronicle, "District 24-6A realignment: Friendswood exits," 1 Feb. 2018 Roth also won three annual PEN/Faulkner Awards for specific works, the biennial PEN/Nabokov Award for a body of work, and, in 2007, the inaugural PEN/Saul Bellow Award for Achievement in American Fiction. Scott Martelle,, "Philip Roth dies at 85; novelist both probed and skewered Jewish American culture," 23 May 2018 The Global Teen Medical Summit is a biennial event started in 2012 by the Health Museum’s Education Team. Alex Park, Houston Chronicle, "Youths explore medicine at Global Teen Medical Summit," 13 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'biennial.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of biennial

1562, in the meaning defined at sense 1

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Statistics for biennial

Last Updated

27 Jan 2019

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The first known use of biennial was in 1562

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English Language Learners Definition of biennial

: happening every two years
of a plant : living for only two years or seasons : having a life cycle that is two years or seasons long


bi·​en·​ni·​al | \ bī-ˈe-nē-əl \

Kids Definition of biennial

 (Entry 1 of 2)

1 : occurring every two years a biennial celebration
2 : growing stalks and leaves one year and flowers and fruit the next before dying

Other Words from biennial

biennially \ -​ē-​ə-​lē \ adverb



Kids Definition of biennial (Entry 2 of 2)

: a biennial plant

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More from Merriam-Webster on biennial

Rhyming Dictionary: Words that rhyme with biennial

Spanish Central: Translation of biennial

Nglish: Translation of biennial for Spanish Speakers Encyclopedia article about biennial

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