Symbols:Greek/Mu

Expectation

 * $\mu$

Often used to denote the expectation of a given random variable.

Linear Density

 * $\mu$

Used to denote the linear density of a given one-dimensional body:
 * $\displaystyle \mu = \frac m l$

where:
 * $m$ is the body's mass;
 * $l$ is the body's length.

Parameter of Poisson Distribution

 * $\mu$

Used as an alternative to $\lambda$ to denote the parameter of a given Poisson distribution.

Moment of Discrete Random Variable

 * $\mu'_n$