CS Knowledge Base

• IPA^(key): /baɪ-/, (rare) /bɪ-/

• Audio (US):

  (file)

PIE word
*dwóh₁

Borrowed from Latin bi-, from Proto-Italic *dwi-, from Proto-Indo-European *dwi-. Doublet of twi- and di-.

• bin- (before some vowel-initial roots)
• bis-
• bir-

Latin number prefix

Previous:	uni-
Next:	tri-

bi-

2. Two in number.

   biarticular is affecting, or connecting two joints; biaxial is along two axes; bicoloured is of two colours

4. Having or possessing two of the root word's quality.

   biangular is having two angles or corners, biantheriferous is having two anthers, bicardial is having two separate hearts, bikont is a eukaryotic cell with two flagella; thought to be the ancestor of all plants

6. Both: referring to two as a set.

   biacetabular is relating to both acetabula, biallelic is of or pertaining to both alleles of a gene, bicaval is relating to both veins of the vena cava

8. Being different in two ways with respect to the root.

   biadjoint is adjoint in two different ways, biaffine is affine in two different ways, biclonal is having cell markers from two different cell lines

10. Forked, divided by two, halved; (chemistry, proscribed) half

    bifurcate is to divide or fork into two channels or branches, bicapitate is to divide something equally between two people or organisations, bicarinate is dividing into two points at the end

12. Double, twofold.

    bialgebroid is a double algebroid, bifarious is twofold, double, biarticulated is doubly articulated

14. (LGBTQ) Bisexual, relating to bisexuality.

    bicentric is having a bisexual bias or basis, biphobia is antipathy towards bisexuals, biromantic is romantically attracted to both males and females

16. (anatomy) Bilateral, on both sides of the body.

    biconcave is having both sides concave, biballism is ballism that affects both sides of the body

18. Twice.

    biannual is occurring twice a year, biannual is something occurring twice each year, biconjugate is paired twice

20. Every two; a rate of once every two.

    biannual is occurring once every two years; biennial, bicentennial is occurring every two hundred (200) years

22. A pair of; composed of two.

    bibrow is a pair of eyebrows which do not meet in the middle, as opposed to a unibrow, bicomplex is composed of a pair of complex numbers having certain defined properties

24. (chemistry) Used for the digit two to form systematic element names of elements whose existence has been predicted, and which have not yet been given a trivial name.

    ‎un- (“1”) + ‎bi- (“2”) + ‎un- (“1”) + ‎-ium (element suffix) → ‎unbiunium (“element 121”)

In an old, common method used to indicate the presence of an acidic hydrogen, sodium hydrogen sulfate is called "sodium bisulfate" and sodium hydrogen carbonate is called "sodium bicarbonate". This method is not recommended by IUPAC and does not denote a “doubling up” of a specific group, which is reserved for the Greek prefix di-, as in carbon dioxide (“CO₂”).

The prefix bi in the older system comes from the observation that there is two times as much carbonate (CO₃) in sodium bicarbonate (NaHCO₃) and other bicarbonates as in sodium carbonate (Na₂CO₃) and other carbonates.

As a prefix for periods, bi- is ambiguously used to mean either “once every two periods” or “twice every period”; this is particularly acute for biweekly, bimonthly, and biannual. To avoid ambiguity, semi- or twice can be used to unambiguously mean “every half period” (thus twice every period) or “twice every period”, but there is no general way to refer unambiguously to “once every two periods”. In some cases a separate word is unambiguous, as in fortnightly (“every two weeks”), or biennial (“every two years”), but there is no word that unambiguously refers to “every two months”. Due to the ambiguity, some prefer to use explicit phrases, like “every two months” or “twice a month”.

• (multiple senses): di-, duo-

From Ancient Greek βίος (bíos, “life”).

bi-

2. (before a vowel) Alternative form of bio-.

   biont is a living organism

• IB, ib.

From Persian بی (bi).

• IPA^(key): [biː]

bi-

1. (rarely productive) -less, un-, in-.

   Synonym: -siz

From Latin bis.

• IPA^(key): (Northern, Balearic, Central, Valencia, Northwestern) [bi]

bi-

1. bi-

• “bi-”, in Diccionari de la llengua catalana [Dictionary of the Catalan Language] (in Catalan), second edition, Institute of Catalan Studies [Catalan: Institut d'Estudis Catalans], April 2007
• “bi-”, in Gran Diccionari de la Llengua Catalana, Grup Enciclopèdia Catalana, 2026
• “bi-” in Diccionari normatiu valencià, Acadèmia Valenciana de la Llengua.

Borrowed from Latin bis.

• IPA^(key): [bɪ ]

bi-

1. bi-

• “bi-”, in Slovník spisovného jazyka českého (in Czech), 1960–1971, 1989

• IPA^(key): [ˈb̥i]

From German bei- (“by-”).

bi-

1. by-, side-

   Synonym: side-

From Latin bis (“twice”).

bi-

1. bi-

   Synonyms: di-, tve-, dobbelt-

Borrowed from Latin bi-.

• IPA^(key): /bi/

bi-

1. bi-

• Most words containing this prefix were not formed in Dutch and instead represent borrowings and internationalisms.

Internationalism (see English bi-), ultimately from Latin bis.

• IPA^(key): /ˈbi-/, [ˈbi-]

bi-

1. (in loanwords) bi- (double, twin)

   Synonyms: see kaksois-

From Latin bis (“twice”).

• IPA^(key): /bi/

• Audio (France (Vosges)):

  (file)

bi-

1. bi-

From Latin bis.

bi-

1. bi-

   Synonyms: bi-, duo-

From

.

• “bi-”, in Dicionario da Real Academia Galega (in Galician), A Coruña: Royal Galician Academy, 2012–2026

From Latin bis (“twice”).

• Audio (Germany (Berlin)):

  (file)

bi-

1. bi-

bi-

1. romanization of 𐌱𐌹-

bi-

1. bi-

Inherited from Malay bi-, from Persian بی.^[1]

bi-

1. (no longer productive) -less; prefix expressing the lack of the root word.

   ‎bi- + ‎adab (“manners, civility”) → ‎biadab (“uncivilized”)

   ‎bi- + ‎adat (“habitude, tradition”) → ‎biadat (“asocial”, literally “uncustomary”)

• While there have been efforts to popularize the use of this prefix in scientific and technological coinages, currently, its range of use is very limited, and so, it is found only in a small number of words.

From Dutch bi-, from Latin bi-.

• IPA^(key): [bi]
• Hyphenation: bi

bi-

1. bi-: two, pair, both

   Synonyms: dwi-, dua

• “bi-”, in Kamus Besar Bahasa Indonesia [Great Dictionary of the Indonesian Language] (in Indonesian), Jakarta: Agency for Language Development and Cultivation – Ministry of Education, Culture, Research, and Technology of the Republic of Indonesia, 2016

bi-

1. alternative form of bith-, used before a slender T.

• Ó Dónaill, Niall (1977), “bit-”, in Foclóir Gaeilge–Béarla [Irish–English Dictionary], Dublin: An Gúm, →ISBN

From Latin bis (“twice”).

• IPA^(key): /bi/
• Hyphenation: bi-

bi-

1. bi-
2. di-

From Proto-Bantu *bì-.

bi- (singular ki-)

1. class 8 prefix
2. class subject concord

From Proto-Italic *dwi-, from Proto-Indo-European *dwi- (“two-; twice-”), prefix form corresponding to the numeral *dwóh₁ (“two”); the origin in PIE of the *i here is uncertain.^[1]

• (Classical Latin) IPA^(key): [ˈbɪ]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈbiː]

bi-

1. having two parts
2. occurring twice

• “bi-”, in Charlton T. Lewis (1891), An Elementary Latin Dictionary, New York: Harper & Brothers
• “bi-” on page 231/3 of the Oxford Latin Dictionary (1st ed., 1968–82)

Borrowed from Persian بی.^[1]

• IPA^(key): /bi/ [bi]
• Hyphenation: bi-

bi- (Jawi spelling بی-)

2. -less; prefix expressing the lack of the root word.

   Synonyms: nir-, nis-

   ‎bi- + ‎adab (“manners”) → ‎biadab (“impolite”)

• While there have been efforts to popularize the use of this prefix in scientific and technological coinages, currently, its range of use is very limited, and so, it is found only in a small number of words.

Borrowed from English bi-, ^[1] from Latin bi- ultimately from Proto-Indo-European *dwi-. Doublet of dwi- via Sanskrit द्वि (dvi)

• (Literary Standard) IPA^(key): /bi/ [bi]

• (English-based) IPA^(key): /ˈbaj/ [ˈbai̯]
• Hyphenation: bi-

bi- (Jawi spelling بی-)

2. (unproductive, fossilized in direct English loans) bi-

   Synonym: dwi-

   biseks ― bisexual

Inherited from Old English be-, from Proto-West Germanic *bi-, from Proto-Germanic *bi-, from *bi-; compare by-.

The pronunciation /bi-/ (instead of expected /bə-/) is probably due to the influence of the preposition by.

• be-, by-
• b- (in certain words)

• IPA^(key): /bi-/

bi-

1. A prefix forming transitive verbs from any content word, often denoting completion or thoroughness.
2. A prefix forming prepositions, often denoting adjacency, position, or relation.

• English: be-
• Scots: be-

• “bi-, pref.(2).”, in MED Online, Ann Arbor, Mich.: University of Michigan, 2007.
• “bi-, pref.(3).”, in MED Online, Ann Arbor, Mich.: University of Michigan, 2007.

bi-

1. alternative form of by-

• IPA^(key): /pɪ̀-/

Cognate with Tanacross u-, Lower Tanana be-, Ahtna u-, Koyukon bi-.

bi-

2. his, her, its, their

   ‎amá (“one's mother”) + ‎bi- → ‎bimá (“his/her/its/their mother”)

This prefix often corresponds to an English possessive ’s appended to the preceding word. For example, Diné bizaad means literally “the People their-language”, equivalent to “the People’s language” (i.e., Navajo language).

• á-
• ał-
• ahił-
• Navajo terms prefixed with bi- (possessive)

  bibaʼ

  Binááʼ Ádaałtsʼózí bichʼil łigaií

  God bidiyin naalʼaʼí

  bikétłʼóól

  bikéyah

  biwááshindoon

bi-

2. Marks a third-person singular indirect object.

• yi- is used in place of bi- when the subject is third person, unless the verb is inverse.

bi-

1. forms the affirmative subjunctive mood of verbs.

bi-

1. by-, by, side
2. bi-

• “bi-” in The Bokmål Dictionary.

bi-

1. by-, by, side
2. bi-

• “bi-” in The Nynorsk Dictionary.

bi-

1. this way, here, hither (toward the speaker)

   Bi-anokiin.

   Come and work.

• biid-

• ani-
• omaa

• The Ojibwe People's Dictionary https://ojibwe.lib.umn.edu/main-entry/bi-pv-dir

From Proto-West Germanic *bi-.

• IPA^(key): /bi-/ (early) ⭢ /bə-/ (late)

bi-

1. A prefix used to make transitive verbs

   ‎bi- + ‎gravan → ‎bigravan

   ‎bi- + ‎kēren → ‎bikēren

   ‎bi- + ‎rādan → ‎birādan

   ‎bi- + ‎*senken → ‎bisenken

   ‎bi- + ‎thecken → ‎bithecken

   ‎bi- + ‎thenken → ‎bithenken

   ‎bi- + ‎wīen → ‎biwīen

• Middle Dutch: be-
  • Dutch: be-
    • Afrikaans: be-
    • Negerhollands: be-
  • Limburgish: be-

From bī.

• IPA^(key): /biː-/

bī-

1. A prefix denoting 'by' or 'near'

   ‎bi- + ‎gardo → ‎bīgardo

   ‎bi- + ‎*fanc → ‎bīfanc

• Middle Dutch: bi-
  • Dutch: bij-

• biġ-, be-

• IPA^(key): /ˈbiː/

From bī (“by, near, around”).

bī-

1. near, around (compare Latin para-)

   ‎bi- + ‎nama → ‎bīnama (“pronoun”)

   ‎bi- + ‎word → ‎bīword (“proverb, byword”)

• Occurred primarily in nouns.

• bīgenga (“inhabitant; observer; benefactor”)
• bīleofa (“support, sustenance, nourishment, capital”)
• bīswæc (“treachery”)

• Middle English: by-, bi-
  • English: by-, be-
  • Scots: by-, be-

bi-

1. alternative form of be-

An unstressed form of bī, from Proto-West Germanic *bī-.

bi-

1. A productive prefix usually used to form verbs and adjectives, especially verbs with the sense “around, throughout” or makes transitive verbs from intransitive verbs, adjectives and nouns.

   ‎bi- + ‎brekan → ‎bibrekan (“to break”)

   ‎bi- + ‎brengian → ‎bibrengian (“to accomplish”)

   ‎bi- + ‎dēlian → ‎bidēlian (“to deprive”)

   ‎bi- + ‎delvan → ‎bidelvan (“to bury”)

   ‎bi- + ‎dempian → ‎bidempian (“to suffocate”)

   ‎bi- + ‎dernian → ‎bidernian (“to conceal, to hide”)

   ‎bi- + ‎dōdian → ‎bidōdian (“to kill”)

   ‎bi- + ‎driogan → ‎bidriogan (“to deceive”)

   ‎bi- + ‎drōragon → ‎bidrōragon (“to bleed to death”)

   ‎bi- + ‎dumbilian → ‎bidumbilian (“to make a fool”)

   ‎bi- + ‎*dwellian → ‎bidwellian (“to hinder”)

   ‎bi- + ‎fāhan → ‎bifāhan (“to embrace, seize”)

   ‎bi- + ‎fallan → ‎bifallan (“to befall”)

   ‎bi- + ‎felhan → ‎bifelhan (“to recommend, give over, confide”)

   ‎bi- + ‎fellian → ‎bifellian (“to throw down”)

   ‎bi- + ‎findan → ‎bifindan (“to notice, find out”)

   ‎bi- + ‎gangan → ‎bigān, bigangan (“to celebrate”)

   ‎bi- + ‎gehan → ‎bigehan (“to dare, confess”)

• be-

From bī (“by, near, around”).

bī-

1. prefix meaning near, around (compare Latin para-), occurring primarily in nouns

   ‎bi- + ‎word → ‎bīword (“proverb, byword”)

• bīgengio (“inhabitant”)

Derived from Latin bi-.

• IPA^(key): /bi/

• Audio:

  (file)

• Rhymes: -i
• Syllabification: bi-

bi-

1. bi-, two

   Synonyms: dwu-, di-, dy-

   ‎bi- + ‎-gamia → ‎bigamia

• “bi-”, in Polish dictionaries at PWN‎^[1] (in Polish)

Borrowed from Latin bis.

bi-

1. bi- (two-)

• “bi-”, in Dicionário Aulete Digital (in Portuguese), Rio de Janeiro: Lexikon Editora Digital, 2008–2026
• “bi-”, in Dicionário Priberam da Língua Portuguesa (in Portuguese), Lisbon: Priberam, 2008–2026

• bis-, biz-

From Latin bis (“twice”).

• IPA^(key): /bi/ [bi]
• Syllabification: bi-

bi-

1. bi-

   Synonyms: di-, duo-

• “bi-”, in Diccionario de la lengua española [Dictionary of the Spanish Language] (in Spanish), online version 23.8.1, Royal Spanish Academy [Spanish: Real Academia Española], 15 December 2025

• IPA^(key): /bi/, [ˈb̥i]

bi-

1. by-, next to, near, by the side, aside; same as English by- and German bei-; see also the rare preposition bi
   1. secondary, subsidiary; subordinate; side

      biroll

      supporting role [side role]

      bisak

      side issue; sideshow; minor issue/matter/detail

      (literally, “side thing/matter [less important thing/matter]”)

      bisats

      subordinate clause

      biklöv

      dewclaw (on the foot of a cloven-hoofed animal)

      (literally, “secondary/subsidiary claw [see also klöv]”)

2. bi-, two, dual; from Latin bis (“twice”)

• hetero-
• homo-

• “bi-”, in Svensk ordbok [Dictionary of Swedish] (in Swedish)
• “bi-”, in Svenska Akademiens ordlista [Wordlist of the Swedish Academy] (in Swedish)
• “bi-”, in Svenska Akademiens ordbok [Dictionary of the Swedish Academy] (in Swedish)

• (before vowels) by-

From Proto-Bantu *bí-.

• IPA^(key): /βi-/

bi-

1. class 8 pronominal concord

   ‎bi- + ‎-nu (“this, these”) → ‎binu (“these (class 8)”)

2. they; class 8 subject concord

   ‎bi- + ‎-kora (“to do”) → ‎bikora (“they (class 8) do”)

3. positive imperative form of -bi- (“them; class 8 object concord”)

   ‎bi- + ‎-ha (“to give”) → ‎biha (“give them (class 8)”)

• Kaji, Shigeki (2007), A Rutooro Vocabulary‎^[2], Tokyo: Research Institute for Languages and Cultures of Asia and Africa (ILCAA), →ISBN, page 414

Borrowed from Persian بی (bi, prefix).

bi-

1. (obsolete, unproductive) -less, un-, in-.

   Synonym: -siz

Compare Navajo bi-, Hupa mi-.

bi-

1. Marks a third person possessor of a noun or object of a postposition.

   ‎-siʼ (“head”) + ‎bi- → ‎bisiʼ (“his/her/their head(s)”)

   ‎-ł (“with”) + ‎bi- → ‎bił (“with him/her/it/them”)

• Begay, Kayla Rae (2017), Wailaki Grammar, University of California, Berkeley, page 220