Bernoulli trial
The Bernoulli distribution models the outcome of a single Bernoulli trial. In other words, it models whether flipping a (possibly biased) coin one time will result in either a success (obtaining a head) or failure (obtaining a tail). The binomial distribution generalizes this to the number of heads from performing "n" independent flips (Bernoulli trials) of the same coin. The multinomial distribution models the outcome of "n" experiments, where the outcome of each trial has a categorical distribution, such as rolling a "k"-sided die "n" times.