For a basic ex definition, it is the phonetic spelling of the 24th letter of the alphabet.
Another ex meaning involves broken relationships. An ex-spouse or an ex-partner is often simply referred to as an ex.
In Latin, the ex meaning is “out of” or “from.” It shows up in phrases like “Deus ex machina.”
You may also see this ex definition on a bookplate identifying the owner of a book. It will read, “Ex libris."
a woman who was formerly a particular man's wife
all his exes live in Texas
out of fashion
a man who was formerly a certain woman's husband
the 24th letter of the Roman alphabet