Definition:String

Definition
Let $\mathcal A$ be an alphabet of symbols.

A string (in $\mathcal A$) is a sequence of symbols from $\mathcal A$.

There is no limit to the number of times a particular symbol may appear in a given string.

Also defined as
Some sources use the word string to mean a finite string, i.e. what we have chosen to call a word.

Also see

 * Substring
 * Initial part
 * Null string
 * Word
 * Concatenation