The latin letter is used in math to represent a variable or coeffecient.
A coeffecient is a constant value in a math expression that is given a symbol to represent it instead of a value.
A variable is a core concept in algebra where a symbol, usualy a lower case latin letter, is used as a placeholder in a math expression.
The Latin Alphabet is a collection of 26 symbols that form the basis of the English language. The alphabet's symbols are used throughout mathematics to represent variables, constants, and coeffecients.
The capital Latin letter B is used in probability as a random variable.