bi

[ bahy ]

/ baɪ /

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adjective, noun, plural bis, bi's.

Slang. bisexual.

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Origin of bi

By shortening

Other definitions for bi (2 of 5)

Symbol, Chemistry.

bismuth.

Other definitions for bi (3 of 5)

abbreviation

plural BI's. built-in.

business intelligence.

Other definitions for bi (4 of 5)

bi-¹

a combining form meaning “twice,” “two,” used in the formation of compound words: bifacial; bifarious.

Compare bin-.

Origin of bi-

<Latin, combining form of bis;see twice

words often confused with bi-

All words except biennial referring to periods of time and prefixed by bi-¹ are potentially ambiguous. Since bi- can be taken to mean either “twice each” or “every two,” a word like biweekly can be understood as “twice each week” or “every two weeks.” To avoid confusion, it is better to use the prefix semi- to mean “twice each” ( semiannual; semimonthly; semiweekly ) or the phrase twice a or twice each ( twice a month; twice a week; twice each year ), and for the other sense to use the phrase every two ( every two months; every two weeks; every two years ).

Other definitions for bi (5 of 5)

bi-²

variant of bio-, especially before a vowel: biopsy.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

WORDS THAT USE BI-

What does bi- mean?

Bi- is a combining form used like a prefix, and it means “two” or “twice.” It is often used in scientific terms, but it crops up in everyday language as well.

Bi- comes from Latin bis, meaning “twice, doubly.” The Greek equivalent of this combining form is di-, as in diacid.

What are variants of bi-?

Bi- is related to the combining form bin– and is used with some words or word elements beginning with vowels. These two forms have similar origins, and for that reason, the difference between the two is a small yet important nuance: bi- often means “twice,” while bin- typically means “double.”

Want to know more? Read our Words That Use bin- article.

Examples of bi-

An example of a word you may have encountered that features bi- is biannual, which can mean either “occurring twice a year” or “occurring every two years.”

Confused? You’re not alone! When it comes to indicating dates on the calendar, bi- likes to have it both ways, as it were. Learn some tips on using biannual and other tricky terms like biweekly here.

We know bi- means “twice,” but what about the -annual portion of the word? You guessed it: -annual means “yearly,” from Latin annuālis. Biannual literally translates to “twice yearly.”

What are some words that use the combining form bi-?

The following words use the equivalent forms of bi- in Latin:

What are some other forms that bi- may be commonly confused with?

There are many words that begin with the letters bi-, such as bias, that do not use the combining form bi- to denote “two.” Learn what words like bias and bilk mean at our entries for these words.

Break it down!

Humans, like many animals, are considered bipeds. The combining form -ped means “(having a) foot.” With this in mind, what is the literal meaning of biped?

How to use bi in a sentence

Are you bi-coastal now, between Portlandia and Late Night with Seth Meyers?
Coffee Talk with Fred Armisen: On ‘Portlandia,’ Meeting Obama, and Taylor Swift’s Greatness|Marlow Stern|January 7, 2015|DAILY BEAST
As a professed bi-sexual, Evans is misunderstood by those who find her choices offensive.
Risky Business or None of Your Business? Gay XXX Films and the Condom Question|Aurora Snow|November 1, 2014|DAILY BEAST
In 2009 Grindr debuted, a dating (or, really, hook-up) app geared towards gay, bi-sexual, and bi-curious men.
Swipe Right For Sex: Mixxxer Is Tinder for the Porn Star Set|Aurora Snow|October 4, 2014|DAILY BEAST
Elsewhere, the bi-communal separation continues, with fierce nationalists seemingly intent on cementing this divide.
The Gaza War Has Left Jerusalem More Divided Than Ever|Peter Schwartzstein|August 24, 2014|DAILY BEAST

The typically somber atmosphere at the bi-annual church convocation was punctuated by hollers, applause and a shout of “brill!”
Church of England Gets Female Bishops and a Conservative Backlash|Nico Hines|July 14, 2014|DAILY BEAST
During the first ten years the sessions were bi-annual, but since 1895 have been held every five years.
Fifty Years of Railway Life in England, Scotland and Ireland|Joseph Tatlow
It seems to me, Hinnissy, that this here thing called bi-ography is a kind iv an offset f'r histhry.
Mr. Dooley Says|Finley Dunne
Histhry lies on wan side, an' bi-ography comes along an' makes it rowl over an' lie on th' other side.
Mr. Dooley Says|Finley Dunne
Th' on'y bi-ography I care about is th' one Mulligan th' stone-cutter will chop out f'r me.
Mr. Dooley Says|Finley Dunne
I like Mulligan's style, f'r he's no flatthrer, an' he has wan model iv bi-ography that he uses f'r old an' young, rich an' poor.
Mr. Dooley Says|Finley Dunne

British Dictionary definitions for bi (1 of 5)

bi¹

/ (baɪ) /

adjective, noun

slang short for bisexual (def. 1), bisexual (def. 6)

British Dictionary definitions for bi (2 of 5)

bi²

the internet domain name for

Burundi

British Dictionary definitions for bi (3 of 5)

the chemical symbol for

bismuth

British Dictionary definitions for bi (4 of 5)

bi-¹

sometimes before a vowel bin-

combining form

two; having twobifocal

occurring every two; lasting for twobiennial

on both sides, surfaces, directions, etcbilateral

occurring twice duringbiweekly

denoting an organic compound containing two identical cyclic hydrocarbon systemsbiphenyl
(rare in technical usage) indicating an acid salt of a dibasic acidsodium bicarbonate
(not in technical usage) equivalent of di- 1 (def. 2a)

Word Origin for bi-

from Latin, from bis twice

British Dictionary definitions for bi (5 of 5)