B

B is the second letter of the Latin alphabet and the first consonant in the English name "bee." It arose from the Phoenician letter beth, which meant "house," and was transmitted to Greek as beta before entering Latin as B. The uppercase and lowercase forms have distinct shapes but share the same origin.

In phonology, B denotes a voiced bilabial stop in many languages. In English it commonly represents the /b/ sound, as in "boy," though its letter can be silent in a few words such as "debt" and "thumb." Across languages, the exact pronunciation of B varies, but it is generally a plosive consonant.

In usage, B serves multiple roles. It is a common initial letter in words and appears in numerous digraphs and clusters. In biology and medicine, B denotes several important concepts, including blood type B and vitamin B in the B-complex group. In computing, the letter B is often used to denote a byte, while b is used for a bit.

In science and mathematics, B appears in various symbolic conventions. In physics, B commonly stands for magnetic flux density. In mathematics and computer science, B can denote a set, a basis, or a variable representing a second component in a pair.

Other domain uses include the musical note B in Western notation, the blue channel in the RGB color model (where B stands for blue), and boron, the chemical element with the symbol B and atomic number 5. The letter also serves in grading systems, abbreviations, and numerous branding and linguistic contexts.