B

 ( Iso Basic Latin Letters ) 

By Byzantine Greek, the Greek letter came to be pronounced /v/, so that it is known in modern Greek as víta (still written βήτα). The Cyrillic letter ve represents the same sound, so a modified form known as be was developed to represent the Slavic languages' /b/. (Modern Greek continues to lack a letter for the voiced bilabial plosive and transliterates such sounds from other languages using the digraph/consonant cluster , mp.)

Old English was originally written in runes, whose equivalent letter was beorc , meaning "birch". Beorc dates to at least the 2nd-century Elder Futhark, which is now thought to have derived from the Old Italic alphabets' either directly or via Latin alphabet .

The Uncial script and half-uncial introduced by the Gregorian and Irish missions gradually developed into the ' . These Old English Latin alphabets supplanted the earlier runes, whose use was fully banned under King Canute in the early 11th century. The Norman Conquest popularised the Carolingian half-uncial forms which latter developed into blackletter . Around 1300, letter case was increasingly distinguished, with capitalization and lower-case B taking separate meanings. Following the advent of printing in the 15th century, the Holy Roman Empire (Germany) and Scandinavia continued to use forms of blackletter (particularly Fraktur), while England eventually adopted the humanist and antiqua scripts developed in Renaissance Italy from a combination of Roman inscriptions and Carolingian texts. The present forms of the English cursive B were developed by the 17th century.

As /b/ is one of the sounds subject to Grimm's Law, words which have in English and other Germanic languages may find their cognates in other Indo-European languages appearing with , , or instead. For example, compare the various cognates of the word . It is the Letter frequency in the English language (after V, K, J, X, Q, and Z), with a frequency of about 1.5% in words.

In Estonian, Danish language, Faroese language, Icelandic, Scottish Gaelic and Mandarin Chinese Pinyin, does not denote a voiced consonant. Instead, it represents a voiceless that contrasts with either a (in Estonian) or an aspirated (in Danish, Faroese, Icelandic, Scottish Gaelic and Pinyin) represented by . In Fijian language represents a prenasalised , whereas in Zulu language and Xhosa language it represents an implosive , in contrast to the digraph which represents . Finnish language uses only in loanwords.

• In the base-16 numbering system, B is a number that corresponds to the number 11 in decimal (base 10) counting.
• B is a musical note. In English-speaking countries, it represents Si, the 12th note of a chromatic scale built on C. In Central Europe and Scandinavia, "B" is used to denote B-flat and the 12th note of the chromatic scale is denoted "H". Archaic forms of 'b', the b quadratum (square b, ) and b rotundum (round b, ) are used in musical notation as the symbols for natural and flat, respectively.
• In Contracted (grade 2) English braille, stands for "but" when in isolation.
• In computer science, B is the symbol for byte, a unit of information storage.
• In engineering, B is the symbol for decibel, a unit of level.
• In chemistry, B is the symbol for boron, a chemical element.

• 𐤁 : Semitic letter Bet, from which the following symbols originally derive
• Β β : Greek alphabet letter Beta, from which B derives
• Ⲃ ⲃ Coptic alphabet letter Bēta, which derives from Greek Beta
• В в : Cyrillic letter Ve, which also derives from Beta
• Б б : Cyrillic letter Be, which also derives from Beta
• ʙ : A small capital B, used as the lowercase B in a number of alphabets during romanization
• 𐌁 : Old Italic B, which derives from Greek Beta
• ᛒ : Runes letter Berkanan, which probably derives from Old Italic B
• 𐌱 : Gothic alphabet letter bercna, which derives from Greek Beta
• IPA-specific symbols related to B: 𐞄 𐞅
• B with : Ƀ ƀ Ḃ ḃ Ḅ ḅ Macron below Ɓ ɓ ᵬ ᶀ
• Ꞗ ꞗ : B with flourish
• ᴃ ᴯ ^{B b} : Barred B and various modifier letters are used in the Uralic Phonetic Alphabet.
• Ƃ ƃ : B with topbar

• ␢ :
• ฿ : Thai baht
• ₿ : Bitcoin
• ♭: The flat in music, mentioned above, still closely resembles lowercase b.

Variant forms of the letter have unique code points for specialist use: the alphanumeric symbols set in mathematics and science, Latin beta in linguistics, and halfwidth and fullwidth forms for legacy CJK characters font compatibility. The Cyrillic and Greek of the Latin have separate encodings: and .