The word string has a number of rather different meanings in modern English, though they are all related in the sense of denoting something long and thin.
- In common speech, it refers to a textile material, use for such things as wrapping packages. Kite string is another example.
- In computer software, it is a sequence of characters. It is sometimes called a "character string". Computer hardware is typically not optimized for the types of operations that programmers like to do, such as concatenating or inserting, because these operations can make strings change size, requiring moving large blocks of memory around. Many ways of dealing with this problem have been devised over the last 60 years, involving efficiency vs. naturalness trade-offs. Some languages, like C and C++, permit efficient string manipulation, at a cost of programmer naturalness and understandability. Others, like LISP and Perl, permit natural use of strings at a cost of efficiency. SQL is sort of between the two.
- String theory is a cutting-edge theory of physics at extremely small scales, postulating that what ordinary quantum mechanics considers to be subatomic particles of size 10−15 meters are actually closed loops, that is strings, of even smaller size.