Definition:Event

Definition
Let $\EE$ be an experiment.

An event in $\EE$ is an element of the event space $\Sigma$ of $\EE$.

Events are usually denoted $A$, $B$, $C$, and so on.

$U$ is often used to denote an event which is certain to occur.

Similarly, $V$ is often used to denote an event which is impossible to occur.

Also defined as
Some sources define an event as a subset of the sample space $\Omega$.

However, while this is technically consistent with the definition as given here, it misses the nuance that it is an element of a specified set of such subsets of $\Omega$ that comprise the event space.

Also known as
An event is also known as a random event.