Definition:Formal Language/Alphabet

 Let $\mathcal L$ be a formal language.

The alphabet $\mathcal A$ of $\mathcal L$ is a set of symbols from which collations in $\mathcal L$ may be constructed.

An alphabet consists of the following parts:


 * The letters
 * The signs.

Depending on the specific nature of any particular formal language, these too may be subcategorized.

Also denoted as
Some sources use $\Sigma$ to denote an arbitrary alphabet.