A pen getting ready to write next to a dollar sign.
dollar sign definition by Webster's New World
dollar sign definition by American Heritage Dictionary
dollar sign - Computer Definition
The dollar sign ($) is sometimes used to indicate a hexadecimal number. For example, $3E0 is the hex number 3E0. In the Unix world, all Unix shells support the use of the $ as a prefix to the name of a shell variable or an environment variable.