Look up B in Wiktionary, the free dictionary.

B is the second letter of the Latin alphabet.

B may also refer to:

Science and technology

• B battery, a battery used to provide the plate voltage of a vacuum tube
• Haplogroup B (mtDNA), a human mitochondrial DNA (mtDNA) haplogroup
• Haplogroup B (Y-DNA), a Y-chromosomal DNA (Y-DNA) haplogroup
• B, Blood type
• ATC code B Blood and blood forming organs, a section of the Anatomical Therapeutic Chemical Classification System
• Boron, a chemical element
• B, B+ and B-, expressions of buoyancy in convective available potential energy
• Bulb (photography), a shutter-speed setting
• B horizon, a layer of soil commonly known as subsoil
• Vitamin B
• Dominical letter B for a common year starting on Saturday
• Hepatitis B

Astronomy

• B, abbreviation for astronomical objects in the Barnard list of dark nebulae
• b represents latitude in the galactic coordinate system

Symbols for physical and chemical quantities and units

• one of the reciprocal lattice vectors (b*)
• breadth (b), see length
• impact parameter (b)
• molality (b)
• barn (unit) (b), a unit of area
• magnetic field (B)
• napierian absorbance (B)
• rotational constant (B)
• second virial coefficient (B)
• susceptance (B)
• boolean domain (${\displaystyle \mathbb {B} }$) in mathematics

Music

• B (musical note)
• B major, a scale
• B minor, a scale
• B major chord, Chord names and symbols (popular music)
• B (I Am Kloot album), a compilation album by I Am Kloot
• B (Battles EP), an extended play by Battles
• b (Moxy Früvous EP), an extended play by Moxy Früvous
• ♭ Flat (music), a note lower in pitch by a semitone
• b, an Iamamiwhoami song
• Charly B (born 1981), the stage name of reggae singer-songwriter Charles Blanvillain
• B, member of Superorganism (band)

Computing and internet

• B (programming language)
• B-Method, for computer software development
• b, bit
• B, byte
• B-tree, a data structure
• <b></b>, an HTML element denoting bold text, see HTML element#b
• /b/, the name of the "random" board on 4chan and other imageboard websites
• Bkonrad, a Wikipedian. Bkonrad especially likes to revert pages about acronyms, often citing the reason as "No indication on the linked article of being known by these initials". He has been reverting an acronym-loving vandal since 2015.

Linguistics

• b, the symbol used in the International Phonetic Alphabet for the voiced bilabial stop
• В, a letter of the Cyrillic alphabet

Media

• b (newspaper), a free daily, tabloid sized newspaper, published by The Baltimore Sun
• Rajawali Televisi, previously name B Channel, Television in Indonesia
• B, the production code for the 1963–64 Doctor Who serial The Daleks
• "B" Is for Burglar, the second novel in Sue Grafton's "Alphabet mystery" series, published in 1985

Sport

• Australian rules football positions#Full back, in Australian Rules football
• B, often used after the name of football clubs to denote a reserve team

Transportation

• B (New York City Subway service)
• Line B (Buenos Aires Metro)
• B (S-train), in Copenhagen
• RER B, a line in the RER of Paris
• B, abbreviation for Bundesstraße (federal highway) in Austria and Germany

Other uses

• Belgium, on the vehicle registration plates of the European Union
• B (grade), for evaluation of students' work
• Codex Vaticanus Graecus 1209, an ancient bible
• Barnabites (Latin: Clerici Regulares Sancti Pauli), a religious order abbreviated to the postnominal B.
• B (bank), a banking brand in the United Kingdom
• Bravo, the military time zone code for UTC+02:00