The following commands are used to define and delete symbols for
    addresses, commands, or values:

    DEFINE                 Defines a symbol as an address, command,
                           or value
    DELETE                 Deletes symbol definitions
    (SET,SHOW) DEFINE      (Establishes, displays) the default
                           qualifier for the DEFINE command
    SHOW SYMBOL/DEFINED    Identifies symbols that have been defined
                           with the DEFINE command