The ampersand (&) normally means "and" as in Jones & Company. However, in the computer world, it is used in various ways. In Windows, it is used as a code to precede an underlined character. As a result, in some input dialogs, you have to enter a double ampersand (&&) to actually define a single ampersand.

In programming, a double ampersand is used to represent the Boolean AND operator such as in the C statement, if (x >= 100 && x >= 199).

In HTML, the ampersand is used to code foreign letters and special characters such as the copyright and trademark symbols. See ampersand codes.