bi-

¹

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

   bifacial; bifarious.

bi-

²

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

   biopsy.

bi

³

[ bahy ]

adjective

, plural bis, bi's.

1. Slang. bisexual.

Bi

⁴

Symbol, Chemistry.

1. bismuth.

BI

⁵

abbreviation for

, plural BI's.

1. plural BIs built-in.
2. business intelligence.

bi-

¹

combining_form

1. See bio-
   a variant of bio-

bi

²

/ baɪ /

adjective

1. See bisexual
   slang.
   short for bisexual bisexual

Bi

³

the chemical symbol for

1. bismuth

bi-

⁴

combining_form

1. two; having two

   bifocal

2. occurring every two; lasting for two

   biennial

3. on both sides, surfaces, directions, etc

   bilateral

4. occurring twice during

   biweekly

5. 1. denoting an organic compound containing two identical cyclic hydrocarbon systems

      biphenyl

   2. (rare in technical usage) indicating an acid salt of a dibasic acid

      sodium bicarbonate

   3. (not in technical usage) equivalent of di- 1

bi

⁵

the internet domain name for

1. Burundi

Confusables Note

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 ).

Word History and Origins

Origin of bi-¹

< Latin, combining form of bis; twice

Origin of bi-²

By shortening

Word History and Origins

Origin of bi-¹

from Latin, from bis twice

Example Sentences

Are you bi-coastal now, between Portlandia and Late Night with Seth Meyers?

From The Daily Beast

As a professed bi-sexual, Evans is misunderstood by those who find her choices offensive.

From The Daily Beast

In 2009 Grindr debuted, a dating (or, really, hook-up) app geared towards gay, bi-sexual, and bi-curious men.

From The Daily Beast

Elsewhere, the bi-communal separation continues, with fierce nationalists seemingly intent on cementing this divide.

From The Daily Beast

The typically somber atmosphere at the bi-annual church convocation was punctuated by hollers, applause and a shout of “brill!”

From The Daily Beast

During the first ten years the sessions were bi-annual, but since 1895 have been held every five years.

From Project Gutenberg

It seems to me, Hinnissy, that this here thing called bi-ography is a kind iv an offset f'r histhry.

From Project Gutenberg

Histhry lies on wan side, an' bi-ography comes along an' makes it rowl over an' lie on th' other side.

From Project Gutenberg

Th' on'y bi-ography I care about is th' one Mulligan th' stone-cutter will chop out f'r me.

From Project Gutenberg

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.

From Project Gutenberg

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-?

• biaxial
• biacetyl
• biathlon
• biangular
• biflex
• bifold
• bihourly
• bijugate
• bimetal
• bimodal
• bimotor
• bipod
• bipedal
• biplane
• bipolar
• biprism
• biparous
• biquarterly
• bisect
• bisexual
• biweekly
• bizonal

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

• biceps
• bicorn
• biennial
• biform
• bimanous
• biped

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

• be-
• biblio-
• bin-
• bio-

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?