# Definition:Word (Formal Systems)

This page is about a finite string of symbols from a given alphabet. For other uses, see Definition:Word.

## Definition

Let $\mathcal A$ be an alphabet.

Then a word in $\mathcal A$ is a juxtaposition of finitely many (primitive) symbols of $\mathcal A$.

Words are the most ubiquitous of collations used for formal languages.

## Also known as

Different treatments of formal languages use different terms for word.

Examples include formula, sentence and string.

However, these alternatives conflict with the concepts logical formula, sentence and string, respectively, in the scope of this site; therefore, their use is discouraged.

It is useful to note that in this context word is a synonym for finite string.