B

B or b may refer to:
* The number 2 in some googologisms, such as billion, boogol and balum
* The base b in BEAF
* The black herd in Archimedes' cattle problem
* An abbreviation for billion, as used in and in Idle Game Maker
* Baby monster group
* Gijswijt's sequence, denoted b(n)
* Busy beaver function