Why is it called a 'String'? [duplicate]

Question

Possible Duplicate:
The History Behind the Definition of a ‘String’…

In most programming languages a string is a sequence of characters. Why is it named that?

The earliest instance of it being called a string is Algol 60 (as far as I know).

Question posed by Douglas Crockford in his talk today (will post when talk is online).

Answer 1

I believe it comes from math theory. Sets, grammars, languages, strings, etc.