What is a tilde key for on a PC?

Certain languages utilize the tilde as a diacritical mark to denote emphasis, but the tilde also represents an approximate number in mathematics when placed in front of a value. On a computer, a tilde is often used to shorten file names or in certain programming languages in functions.

On a typical personal computer, the tilde key is located just below the escape button to allow a user to type a tilde character on the screen. On English keyboards, "shift" must be held down when pressing the tilde key; otherwise the typist will create a back quote symbol instead.