Ex

Ex can refer to various things.

ex (editor), short for Extended, is a line editor developed for the UNIX operating system.
In English, Ex is a common spelling of the English name of the letter X.
In typesetting, one ex is the height of the lowercase letter 'x' in a given font; see x-height.
In Latin, ex means "out of".
In social relationships, an ex (relationship) is someone with whom a person was once associated, often romantically.
As a prefix, ex- generally denotes the former state of something.
In the context of current French politics, the Ex is Valéry Giscard d'Estaing, a former president.
The Ex is a Dutch punk band.