Ampersand in computing

Ampersand is a common symbol for “and”, used as the “address of” operator in C, the “reference” operator in C++ and a bitwise AND operator in several programming languages.
UNIX shells use the character to indicate that a task should be run in the background. That is, the process started by the command can continue to operate even if other commands are subsequently entered at the command line.
The ampersand symbol was incorporated into standard typewriter keyboards, and subsequently into computer keyboards, which are based on typewriter keyboards. It was also incorporated into ASCII (American Standard Code for Information Interchange), the de facto standard for the character encoding used by computers and communications equipment to represent text.

Ampersand in standard generalized markup language

In SGML (standard generalized markup language) and its descendants, such as HTML (hypertext markup language) and XML (extensible markup language), the ampersand is used to begin the encoding that represents a special character (i.e., a character that is not included in the limited standard character set), and such encoding is terminated with a semicolon.

For example, the HTML encoding for the at symbol (@) so that it will render correctly in a web browser is @, and the encoding for the copyright symbol (©) is ©. The ampersand can be encoded with a choice of & and &#amp;.