bi
adjective
bi
1 American
[bahy]
/ baɪ /
adjective
-
bis,
plural
-
bi's
plural
Bi
2
American
Symbol, Chemistry.
BI
3
American
bi-
4
American
bi-
5
American
bi-
1
British
combining form
-
two; having two
bifocal
-
occurring every two; lasting for two
biennial
-
on both sides, surfaces, directions, etc
bilateral
-
occurring twice during
biweekly
-
-
denoting an organic compound containing two identical cyclic hydrocarbon systems
biphenyl
-
(rare in technical usage) indicating an acid salt of a dibasic acid
sodium bicarbonate
-
(not in technical usage) equivalent of di- 1
-
Bi
2
British
symbol
bi
3
British
/ baɪ /
adjective
bi-
4
British
combining form
bi
5
British
abbreviation
Usage
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.
Commonly Confused
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 ).
Etymology
Origin of bi1
By shortening
Origin of bi-4
< Latin, combining form of bis; see twice
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
“We were talking about doing something bicultural, bilingual, bi la, la, la,” Romero, 83, says.
From Los Angeles Times ● Dec. 30, 2024
They’re the default, and then there’s one variable, that they’re gay, or bi.
From New York Times ● Aug. 4, 2023
I lived on Capitol Hill, I was a bi woman surrounded by gay men and a few women, who were most of my community.
From Seattle Times ● Jun. 1, 2023
She said it was "really welcome" that bi people were becoming "much more visible" but said biphobia was still "really common".
From BBC ● Oct. 5, 2022
In practice, bi sometimes means semi, and semi sometimes means bi.
From "Woe Is I" by Patricia T. O'Conner
"In several hundred years, this is the first time the water has reached the second floor... Never before in history," said another resident, Bi Yunchun.
From Barron's ● Jul. 9, 2026
Bi throws his lot in with the monsters and “Resurrection” concludes with a personal and artistic reckoning that’s as defiant and emotional as anything cinema has produced in recent years.
From Los Angeles Times ● Dec. 12, 2025
One of the men, Theodore Bi, called the work “an idea anyone can get behind” and said they had intended to give it as a gift to Elon Musk.
From New York Times ● Nov. 20, 2024
The Pantastic Bi-Mo Bi-Bar Pride 2024: Join the Seattle Pan Bi Alliance this Pride month for this bimonthly Pantastic Bi-Mo Bi-Bar to meet up with other bi/pan+ folks for drinks and conversation.
From Seattle Times ● May 31, 2024
“Bwana and Bi Bolaji, thank you for coming so quickly.”
From "Beasts of Prey" by Ayana Gray
However, inflation is expected to remain within Bank Indonesia’s target range, which could allow BI to keep its focus on exchange-rate stability rather than respond to inflation, she added.
From The Wall Street Journal ● Sep. 25, 2026
Having a seasoned BI official at the helm would also signal the government’s preference for a technocratic, market-oriented transition, DBS economists Taimur Baig and Chua Han Teng said in a recent note.
From The Wall Street Journal ● Aug. 19, 2026
Others, including at ING, think BI will hold steady after the off-cycle move.
From The Wall Street Journal ● Jun. 12, 2026
But as geopolitical uncertainty keeps driving safe-haven demand for the dollar and Indonesia’s new fuel subsidies add to existing fiscal pressures, there are doubts about how much the BI can really do.
From The Wall Street Journal ● May 6, 2026
You've not read a word since I put you in that corner ten minutes ago; Bill and I've fought the battle of Waterloo since dinner, and you've not learned BA BE BI BO.
From Verses for Children and Songs for Music by Juliana Horatia Gatty Ewing
Many were taking selfies with a three-metre-tall Unitree GD01, a towering rideable robot the firm says can switch between bi- and quadruped settings.
From Barron's ● Aug. 19, 2026
However, at that time I was watching a lot of Netflix and I was getting more and more recommendations for series with lesbian storylines, or bi- characters.
From BBC ● Aug. 12, 2023
Two replication forks are formed at the origin of replication and these get extended bi- directionally as replication proceeds.
From Textbooks ● Jun. 9, 2022
Kids who grow up bi- or even trilingual may appear delayed in any one language, simply because they’re splitting the number of words they know between languages.
From Slate ● Nov. 14, 2019
Two of the heaviest crosses to both the child and mother lie in his bi- and tri-daily difficulties with clothing, and prolonged initiation to the sacred mysteries of the table.
From The Forerunner, Volume 1 (1909-1910) by Charlotte Perkins Gilman
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
