Definition of Poisson distribution
: a probability density function that is often used as a mathematical model of the number of outcomes obtained in a suitable interval of time and space, that has its mean equal to its variance, that is used as an approximation to the binomial distribution, and that has the form {latex}f(x) = \frac{e^{-\mu}\mu^{x}}{{x!}}{/latex} where μ is the mean and x takes on nonnegative integral values
