biennial

adjective

bi·​en·​ni·​al (ˌ)bī-ˈe-nē-əl 

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.

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

How to spot it The biennial herbaceous plant poison hemlock, a member of the carrot family, was brought to North America as an ornamental plant from Europe, its native region, according to the Minnesota Department of Agriculture. —Mariyam Muhammad, The Enquirer, 30 May 2024

What starts as a one-time sunset could all too easily become a biennial legislative Christmas tree certain to be weaponized for partisan political gamesmanship. —Jon Brodkin, Ars Technica, 22 May 2024

As a native annual or biennial, an individual yellow corydalis plant is short-lived but can self-seed in habitats with a bit of soil disturbance that keeps its seeds germinating each year. —Miri Talabac, Baltimore Sun, 18 Apr. 2024

Roughly 200 parents, teachers, high school students and community activists gathered in support of Danbury International Academy Charter School and Capital Prep Middletown — two charter schools that weren’t included in the biennial state budget passed by the General Assembly last year. —Ally Lemaster, Hartford Courant, 30 Mar. 2024

Word History

First Known Use

1562, in the meaning defined at sense 1

Kids Definition

biennial

adjective

bi·​en·​ni·​al (ˈ)bī-ˈen-ē-əl 

1

: occurring every two years

2

: growing stalks and leaves one year and flowers and fruit the next before dying

biennial noun

biennially

-ē-ə-lē 

adverb