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.