Library /sys$common/syshlp/dbg$help.hlb DEBUG, DEFINE, Parameters  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 symbol-name

    Specifies a symbolic name to be assigned to an address, command,
    or value. The symbolic name can be composed of alphanumeric
    characters and underscores. The debugger converts lowercase
    alphabetic characters to uppercase. The first character must not
    be a number. The symbolic name must be no more than 31 characters
    long.

 parameter

    Depends on the qualifier specified.